Since the first source of the obligation of maaser kesafim is in this week’s parsha…

Question #1: Paying for Your Kids in Kollel

“I agreed to support my married children for five years. May I use maaser money for this?”

Question #2: Chomesh

What is chomesh?

Question #3: Tuition

May I pay tuition out of maaser kesafim funds?

Question #4: Testing Hashem!

May I ask Hashem to pay me back for the tzedakah money that I give?

Which maaser?

We should first note that the term maaser, without specifying which one, is used sometimes in the Mishnah and Gemara to refer to maaser rishon, and sometimes to refer to maaser sheini, and, in later halachic works, sometimes also to maaser kesafim. These three types of maaser have vastly different laws from one another. Usually, one can understand from context which maaser is intended. If the context alludes to maaser owned by a Levi, or to the first maaser being separated, maaser rishon is intended. If it refers to something that has sanctity, usually maaser sheini is intended. If it refers to a percentage of one’s income that is donated to tzedakah, it refers to maaser kesafim.

The above questions all relate to shaylos about how much someone should donate to tzedakah and how he should prioritize his giving. It is well known that Rav Moshe Feinstein used to complain that these are areas of halacha about which he was asked too infrequently.

Maaser kesafim: giving ten percent of one’s moneys to tzedakah. The poskim dispute whether one subtracts household expenses from one’s income, before calculating maaser.

The concept of maaser is primarily in the case of ayn ani bifanav, when I fulfill the mitzvah by putting aside money for tzedakah. In a case of ani bifanav I do not fulfill my mitzvah by giving him only ten percent.

A person who distributes maaser kesafim to the poor is blessed with a special guarantee of wealth (Taanis 9a). This beracha happens only when someone is meticulous to calculate exactly a tenth of one’s income for tzedakah (Shu’t Avkas Rocheil #3). Furthermore, this beracha is fulfilled only if one gives this maaser money to the poor, but if one gives part of it to other causes, there is no guarantee that wealth will follow (see Shu’t Radbaz 3:441). Therefore, although one may use maaser kesafim to buy an aliyah, pay for a “mi’shebeirach,” purchase sefarim that will be used by the tzibur (Taz, Yoreh Deah 249:1) or similar communal needs, it is preferred to earmark maaser kesafim for the needs of the poor (Rema, Yoreh Deah 249:1). Donations to Torah institutions are considered distributions to the poor (Ahavas Chesed 2:19:2), as are hachnasas kallah expenses (to pay wedding and related expenses for a poor groom or bride).

Chomesh: giving twenty percent of one’s moneys to tzedakah. This is the optimal level of fulfilling mitzvas tzedakah, whereas setting aside ten percent is considered only “midah beinonis,” an average person’s conduct. Someone who gives a chomesh to tzedakah should first calculate and set aside one tenth, and then a second tenth.

Before starting to give regular amounts of tzedakah on an ongoing basis, one should declare that he is following this procedure bli neder, without accepting it as a vow.

Paying for Your Kids in Kollel from Maaser Money

“I agreed to support my married children for five years. May I use maaser money for this?”

The Chasam Sofer authored a responsum (Shu’t Chasam Sofer, Yoreh Deah #231) on this subject, which is fascinating for the many different halachic issues that he clarifies. Someone had arranged the marriage of his scholarly son to the daughter of a talmid chacham,with the following understanding: The father of the son accepted that he would pay every week a certain amount to his mechutan, the bride’s father, who would sustain the young growing family in his home, thus enabling the son-in-law to continue his studies under his father-in-law’s direction. The father of the chosson realized that it will be difficult for him to meet this commitment, and wants to know if he can use the maaser money from his business endeavors to provide the support for which he is responsible.

The Chasam Sofer opens his discussion by quoting two opinions that seem to dispute whether it is acceptable to use maaser money for such an expenditure. The Rema, quoting the Maharil, contends that it is not permitted to use maaser money to pay for a mitzvah, such as donating lamps and candles to the shul, whereas the Shach states, in the name of the Maharam, that it is permitted to use maaser money for mitzvos. Thus, whether one may pay for mitzvos, other than supporting the poor, from maaser money appears to be a dispute among early authorities.

The Chasam Sofer then quotes the Be’er Hagolah, who explains that the two above-quoted opinions are not in dispute. All authorities prohibit using maaser money to fulfill a mitzvah that someone is already obligated to observe. The Maharam, who permitted using maaser money for these purposes, was discussing a case in which the donor intended to use maaser money for this mitzvah from the outset, whereas the Maharil is discussing a situation in which he has been using his maaser money to support the poor, in which case he cannot now divert it for other mitzvos that do not qualify as tzedakah for the poor. Thus, according to the Be’er Hagolah, whether the father can begin meeting his obligations to his son and mechutan with his maaser money will depend on whether he has already accepted the obligation on himself to pay this from other funds, in which case he cannotuse maaser money for it, or if it is an obligation that he is now accepting upon himself, in which case he can specify that he wants to use maaser money to fulfill it.

The Chasam Sofer does not consider the approach of the Be’er Hagolah to be fully correct. He (the Chasam Sofer) notes that the Maharil wrote that maaser moneys are meant to support the poor and not for the acquisition of mitzvos. Therefore, use of maaser money for any type of personal mitzvah is inappropriate, whether he is already obligated to fulfill the mitzvah or not.

The Chasam Sofer concludes that when someone begins donating maaser money, he may stipulate that, sometimes, the money will be used for a mitzvah donation, such as the lighting in shul. However, once he has begun donating his maaser money regularly to the poor, he must continue using it for tzedakah.

Family first

Having determined that there are definitely situations in which maaser money must be given to the poor, the Chasam Sofer then discusses when and whether money designated for the poor can be used to support an individual’s extended family. There is a general rule that one is obligated to the poor to whom one is closest – close family first, more distant family next, neighbors third, members of one’s city next and the out-of-town poor next.

Greater needs

Notwithstanding that family should be supported first, the Chasam Sofer quotes from his rebbi, the author of the Haflaah, that the rules of “closest first” or “family first” are only when the funds are necessary for the same level of need, for example, all have enough to eat, but not enough for clothing. However, if some are short of food, and others have enough to eat but are short on clothing or other needs, the responsibility to make sure that someone has enough to eat comes first, even for someone out of town, regardless of whether there are neighbors or locals who are needy, as long as they have sufficient food.

Yet, concludes the Chasam Sofer, this prioritization is not absolute. All needs of someone’s family are considered his responsibility before the basic needs of others. In other words, the priorities should be as follows:

(1) Family needs.

(2) Most basic needs – food – regardless of location of needy.

(3) People of one’s city.

(4) The out-of-town poor.

Chasam Sofer’s conclusion

If the father had stipulated, at the time of obligating himself to support his son, that he would use maaser money for this obligation, he would be able to use it. Even then, the Chasam Sofer recommends that he use only up to half of his available maaser money to support his son. His reasoning is based on a Mishnah (Peah 8:6) which says that someone is permitted to save his maaser ani (the tithe one gives to the poor in the third and sixth year of the shemittah cycle) to support those that he chooses to, but he should not set aside more than half of his maaser ani for this purpose; the rest should be given to the local poor.

However, this is only when he had originally planned to use maaser money for this purpose. Otherwise, once he created an obligation upon himself to support his son, it is similar to any other obligation that he has, and he may not use his maaser money for this purpose.

Tuition

Rav Moshe Feinstein ruled that one should not pay tuition for sons and daughters in elementary school and high school from maaser funds, because this level of education is obligatory. However, someone eligible for a tuition reduction who elects to pay full tuition may pay the extra from maaser (Shu’t Igros Moshe, Yoreh Deah 2:113; also see Ahavas Chesed 2:19:2). If paying the expected amount of tuition without resorting to maaser funds creates hardship, one should ask a shaylah.

Yeshiva gedolah tuition and expenses may be paid from maaser, because a parent is not obligated to support a child at this age.

Testing Hashem!

At this point, let us discuss the last of our opening questions: “May I ask Hashem to pay me back for the tzedakah money that I give?”

It is generally prohibited to “test” Hashem, as the Torah states, “Lo senasu es Hashem,” “Do not test Hashem” (Devarim 6:16). One may not say, “I am performing this mitzvah so that Hashem will reward me by providing me with such-and-such (Sefer Yerei’im #361; Sefer Hachinuch, Mitzvah 395, 424; Shu’t Radbaz #882).

However, there is one exception to this rule – one may give maaser kesafim, expecting to be blessed with wealth as a reward (Taanis 9a, as explained by Shu’t Avkas Rocheil #3; Sefer Hassidim #144; Rema, Yoreh Deah 247:4; Ahavas Chesed 2:18. Cf. Shel”a and She’ei’las Ya’avetz #3, quoted in Pischei Teshuvah 247:2).

The Gemara (Taanis 9a) relates that, after Reish Lakeish’s passing, Rabbi Yochanan encountered his nephew (who was Reish Lakeish’s son). Rabbi Yochanan asked his nephew what he had learned in cheder that day. The nephew replied, “Te’aser kedei shetis’asher,” “Give maaser so that you get rich.”

“How do you know?” asked Rabbi Yochanan.

“Go test it,” answered the nephew, who then asked, “But is one permitted to test Hashem?”

Rabbi Yochanan replied, “I heard from my rebbe, Rabbi Hoshiyah, that this is an exception –because of the pasuk in Malachi (3:10), where Hashem begs us to test Him when giving maaser and see for yourself that He opens the windows of Heaven and grants blessings until our lips weary of saying ‘Enough!’”

We see from this that it is permitted to declare that I am giving the correct amount of tzedakah and expect that Hashem will reward me with wealth. I know several people who personally attest that this beracha was fulfilled!

Question #1: Grapes

Why is kilayim of grapes different from all the other kilayim prohibitions?

Question #2: Great Auks

Is it permitted to crossbreed auks and ducks?

Question #3: The Grand, Green Movers

I am green. Instead of trucks, may I use elephants, water buffalo and draft horses together to move my house?

Question #4: Accused of Graft!

Where does the Torah prohibit grafting trees?

Introduction:

In parshas Bereishis, the various species of animals and plants were instructed to reproduce lemi’neihem, according to their species, meaning that they were not to hybridize (crossbreed) with other species. These sources in parshas Bereishis bring to mind the several mitzvos taught later in the Torah not to mix species(Chullin 60a; Tosafos, Sanhedrin 60a; Ramban, Bereishis 1:26; Rashbam, Vayikra 19:19).

The word kilayim is translated by Onkelos and ibn Ezra (Vayikra 19:19) as “mixture,” although other commentaries understand that this word originates from the same Hebrew root as the word “prison,” beis ke’le (see Yeshayah, 42:22). This approach is quoted in the name of the Raavad (by the Rashas, in his commentary to the Yerushalmi, Kilayim 3:5) and by Rav Hirsch (Vayikra 19:19), who explains that the shoresh כ ל א means to keep or hold something back, and that the plural structure kilayim is similar to yadayim “hands” or raglayim “feet,” and means a pair. Therefore, the word kilayim means to treat as a pair two items (similar to our pair of hands) that are required to be kept separate.

Having explained the source of the word kilayim this way, there is no need to assume that Onkelos or ibn Ezra disagree. They are merely elucidating the word in the context of the posuk, where it means a forbidden mixture, whereas Rav Hirsch is explaining the etymological basis for this meaning.

Kilayim versus hybridization

It is important to clarify a common misconception. The prohibition of kilayim is not necessarily the creation of a new species — it is the appearance that one is mingling two species together. My desktop dictionary defines hybrid as “the offspring produced by breeding plants or animals of different varieties, species, or races.” Hybridization always involves making changes in the DNA of a species; most instances of kilayim do not. Planting seeds of different species in close proximity does not affect their genetic makeup – thus, technically, no hybridization transpires — yet it may be prohibited min haTorah. Similarly, wearing a garment manufactured from woolen and linen thread does not affect the two parent species or the DNA of the thread in the slightest.

Kilayim prohibitions

The Torah teaches about kilayim in two places, in parshas Kedoshim and in parshas Ki Seitzei. There the Torah mentions a total of six lo saaseh prohibitions, each of which is counted among the 365 lo saasehs that are included in the 613 mitzvos.

In parshas Kedoshim (Vayikra 19:19), the Torah teaches:

(1) Observe my laws! Do not mate your animal with a diverse species (kilayim).

(2) Do not plant your field with a diverse species.

(3) A garment containing diverse species called shatnez you shall not put upon yourself.

In parshas Ki Seitzei (Devorim 22:9-12), the Torah states:

(4) Do not plant diverse species in your vineyard

(5) lest what grows become sanctified (tukdash); the seed that was planted together with the growth of the vineyard.

(6) Do not plow with an ox and a donkey together.

(3, again) Do not wear shatnez, wool and linen together.

Of the six lo saaseh prohibitions counted here, the Torah calls four of them kilayim (which we translated as “diverse species”). The fifth, “lo sacharosh,” do not plow, prohibits different species of animals working together, such as plowing or pulling wagons, but is not called kilayim by the Torah.

The sixth is a prohibition against using what grew as kilayim in a vineyard. There is no prohibition in using any of the other mixtures, meaning that, although it is forbidden to hybridize different species of animals, crossbreed fruit, or plow with different species of animals, it is permitted to eat a crossbred fruit or what grew in a kilayim field other than a vineyard. Similarly, it is permitted to use a shatnez garment as long as I don’t wear it.

Grapes are different!

This leads us to our opening question: “Why is kilayim of grapes different from all the other kilayim prohibitions?” The product of kilayim of other species, including the fruit created by grafting and the mule created by mating a male donkey (jack) with a mare (female horse), are permitted to be used, even if a Jew created them in violation of the halacha. Only in the instance of kil’ei hakerem is there a prohibition to use what is produced.

This prohibition is derived from a careful reading of the pasuk, where the Torah states: Do not plant diverse species in your vineyard lest what grows become sanctified (tukdash); the seed that was planted together with the growth of the vineyard. None of the other kilayim prohibitions include an additional lo saaseh that applies to what grows afterward. The Torah’s method of conveying this law is the word tukdash. The Rashbam explains the word tukdash to mean sanctified — the produce becomes prohibited like kodashim are prohibited for personal use. Although other rishonim have different explanations of the word tukdash, all agree that the produce that grows there is prohibited for use min haTorah.

Why are vineyards different?

Why does the prohibition against benefitting exist only with regard to kilayim in a vineyard? The Chizkuni (Devorim 22:9) explains because otherwise this type of kilayim can slip by unnoticed; the wheat that grows in a vineyard does not look different from wheat grown in a wheat field, as opposed to shatnez and animal husbandry, where the item worn or produced is noticeable that it includes two different “species.” Note that the grafting of a tree is similarly highly noticeable, at least initially.

Animal Hybrids

Thousands of years ago, mankind crossbred horses and donkeys to create mules and hinnies. This hybrid, called a pered (female pirdah) is already mentioned many times in Tanach. As a pack animal, the mule, produced from a male donkey and a mare, may have advantages over either of its parents. It is usually as strong as a horse, yet sturdier and more sure-footed, and — notwithstanding its reputation for being “stubborn as a mule” — is often more reliable for hauling than draft horses. (A hinney, which has less commercial value, is produced from a female donkey [jenny] and a stallion.)

Not only is it prohibited to crossbreed a horse with a donkey, it is even forbidden to mate a mule or hinney with either a donkey or horse (Mishnah, Kilayim 1:6). In fact, it is rare that such an attempt will produce offspring, although it is claimed anecdotally that there are occasions in which a mule or hinney is fertile and reproduces.

Other crossbred animals

Artificial insemination has been used to crossbreed all sorts of species. Camels and llamas have been crossbred with the goal of producing a larger quantity of quality llama wool. Mankind has created such interesting creatures as ligers (crossbreeds of male lions and tigresses), tiglons (sometimes called tigons, from male tigers and lionesses), leopons (male leopards and lionesses), wholpins (whales and dolphins) and geeps (goats and sheep). Most of these have resulted in limited, if any, commercial value, although individuals unconcerned about the halachic ramifications thought that offspring of such crossbreeding might provide an economic advantage. Crossbreeding animal species is one of the prohibitions of the Torah, when it declares behemtecha lo sarbia kilayim (Vayikra 19:19).

Great auks

At this point, let us discuss the second of our opening questions: “Is it permitted to crossbreed auks and ducks?”

Although both varieties of birds spend much time in and over water, I presume that there would be a kilayim prohibition involved in attempting to crossbreed them. There is an additional problem in attempting to crossbreed great auks with ducks, since great auks have been assumed extinct for well over a century.

Pulling your weight

A similar question would be whether a circus show could use species of different animals to haul together. We know that the Torah prohibited this when it wrote lo sacharosh beshor vachamor yachdav, Do not plow with an ox and a donkey together. The juxtaposition of this mitzvah between other kilayim prohibitions implies that this is an extension of the laws of kilayim.

Some rishonim explain that the prohibition of having two different species haul a load together is a type of min haTorah gezeirah to avoid housing them together at night, which (they contend) would be prohibited as crossbreeding animals. We do find other instances of Torah prohibitions whose purpose is to prevent a more serious violation of the Torah. The classic example of this is the prohibition of bal yematzei, owning chometz on Pesach, which the Torah itself states is to avoid violating the more serious prohibition of eating chometz on Pesach (Shemos 12:19). A similar idea is yichud, which the Gemara (Kiddushin 80b) implies is a Torah violation, whose purpose is to discourage the more serious violation of arayos.

Unfair labor practices?

Notwithstanding that the Torah and the Mishnah both imply that the prohibition of lo sacharosh is because of kilayim, many early authorities explain this law because of other reasons. The ibn Ezra  explains that this is prohibited because, although a donkey is an excellent work animal, it is not “strong as an ox.” In other words, the “reason” for this mitzvah is to teach us to be concerned not to overburden the donkey.

I want to show a reverse case. During a tour I once took of a reconstructed nineteenth-century farm, the plow was being pulled by a draft horse together with a mule. The curators explained to me that they own both horses and mules, and teaming up to work together depends on the animal’s temperament, not necessarily its species. They can sometimes successfully team together a particular mule and a particular horse, and sometimes two horses or two mules will not pull their weight together. Apparently, in the animal world, your coworker is as important a factor in job satisfaction as it is in the human world.

However, from a halachic perspective, there are several unusual factors here. For one, mules are the offspring of male donkeys and mares (female horses). The halacha is that teaming a mule and a horse is prohibited min haTorah because they are different species, notwithstanding that their size and strength may be functionally equivalent. In other words, the reason that the ibn Ezra presents for the prohibition of lo sacharosh does not fit the halacha. Furthermore, the mitzvah of lo sacharosh permits matching a large mature draft horse with an undersized pony colt, notwithstanding that the young and small pony will have a very difficult time pulling its weight alongside its powerful coworker.

Nevertheless, we could still accept the ibn Ezra’s approach to analyzing the “reason” for this mitzvah. As noted by the Sefer Hachinuch, we can never, and should never, claim to understand the “reason” for a mitzvah. Why Hashem commanded us to perform a specific mitzvah is not something for us to try to prove or to rationalize. Unfortunately, such rationalizing has often led to individuals not complying with mitzvos. We know that this error was perpetrated even by the greatest of the great – for example, by Shelomo Hamelech when he accrued more wealth and wives than the Torah permits. The Sefer Hachinuch explains that taamei hamitzvah does not mean “reasons” for mitzvos, but that the word taam should be translated here as “taste,” meaning that these are ideas, messages, or tastes that we can apply to ourselves as lessons when we observe or study these mitzvos. The Rambam also agrees that “reasons” or “tastes” of mitzvos do not always reflect the halachic reality. (Those who oppose this approach to taamei hamitzvah rally around Rav Hirsch, who usually espouses reasons for mitzvos only after a highly detailed analysis of all its laws, and suggests taamei hamitzvah only when they fit the halachic details of the mitzvah.)

Graft

At this point, I am returning to the last question that I asked: “Where does the Torah prohibit grafting trees?” If we look carefully at the pesukim of kilayim prohibitions, quoted above, we will note that nowhere does the Torah explicitly prohibit the grafting of one species of fruit tree onto another, which is called in Hebrew harkavah. If, indeed, this prohibition is not mentioned in the Torah, how do we know that it is prohibited?

By means of a complicated homiletic derivation, based on the first words of the pasuk, Observe my laws, the Gemara  (Kiddushin 39a; Sanhedrin 60a) derives that harkavah, grafting a fruit tree onto a different species, is prohibited min haTorah. The Rambam (Hilchos Kilayim 1:5) concludes that it is included under the lo saaseh of sadecha lo sizra kilayim, the prohibition of planting different species of grains together.

Crossbreeding of plants

Crossbreeding of plants, or, as it is usually called, cross-fertilization or cross-pollination, is when one pollinates the flower of one species with pollen from a different species to produce offspring with some characteristics of each. Many fruits have been developed this way, although I want to share that a nectarine is not a crossbreed of a peach and a plum, as is often mistakenly thought. A nectarine is an ancient variety of peach (Prunus persica) that has a smooth skin. Botanists consider it to be the same species as peach. In their opinion, the difference between nectarines and peaches is the difference between two people who have different complexions or perhaps variant orientations of skin pigment, and certainly not a halachic consideration. I am unaware of anyone who has attempted to study this as a halachic issue. The practical difference is whether it is permitted to graft a nectarine scion onto a peach stalk or vice versa.

What is interesting is that, in the discussions about kilayim in the Torah, the Mishnah and the writings of Chazal, nowhere does it say that it is prohibited to cross-pollinate from one plant species to another. This does not mean to say that there is no prohibition of kilayim germane to trees or plants. Quite the contrary, there are three such prohibitions min haTorah. They are referred to as kil’ei zera’im (kilayim in plants), kil’ei hakerem (kilayim in vineyards), and harkavas ilan (kilayim in trees). But, as we will soon see, none of these three prohibitions has to do with crossbreeding.

The prohibition applies to herbaceous, as opposed to woody plants, meaning that it does not apply to trees and shrubs, but it does apply to vegetables and many herbs. Thus, one may plant seeds of different trees together, yet one is forbidden to plant a mix of vegetable seeds (Rambam, Hilchos Kilayim 1:6).

Kil’ei zera’im

Kil’ei zera’im is planting two or more different species of grains, vegetables or other edible herbaceous plants in close proximity. Exactly what defines “close proximity” is a very complicated halachic topic, and depends on factors such as the shape and size of the vegetable patch, and what variety of produce one is planting. We should note that from a botanical point of view, planting two species in close proximity will not cause hybridization because it does not affect the genetic makeup of the species.

The mitzvah of kil’ei zera’im applies only in Eretz Yisrael. Thus, someone in chutz la’aretz may plant his backyard garden with a wide variety of vegetables without any halachic concern, whereas in Eretz Yisrael someone planting a garden patch must be very careful to keep the different species separate.

Kilayim in a vineyard, kil’ei hakerem

Kil’ei hakerem is the prohibition against planting grains or vegetables in or near a vineyard. Again, this forbidden planting will not affect the genetic makeup of any of the plants involved. It is also quite clear that this was not the concern in halacha, as we see from many of the halachic details. For example: although it is prohibited to plant grains or vegetables near a vineyard, it is permitted to separate the vegetable patch from the vineyard by placing a halachic wall between them. For this, two poles and a wire at the top, a tzuras hapesach, between the vegetable patch and the vineyard suffices (Eruvin 11a), similar to what we do when we construct an eruv to permit carrying on Shabbos.

It is quite clear that, botanically, the tzuras hapesach does not prevent the mingling of the species. Yet, with the tzuras hapesach, it is permitted to plant the grain and, without it, there is a Torah prohibition to do so! This certainly cannot be explained on a scientific basis.

Conclusion

Observing and studying the laws of kilayim reminds us how all of Hashem’s creation always follows His instructions. This reminds the contemplative Jew that, if the plants heed Hashem’s word, how much more must we strive to obey His instructions.

The Gemara tells us that the Torah reading of Sukkos includes references concerning gifts to the poor, to remind people of these mitzvos during harvest season.

Question #1: Leaving in Today’s World

“Is there a requirement to leave leket, shich’cha and pei’ah in your field today?”

Question #2: In Chutz La’Aretz

“I live in chutz la’aretz. Am I required to separate pei’ah on my backyard vegetable patch?”

Question #3: Cluster Alms

“Why do I need to know how a typical cluster of grapes looks?

Introduction

While harvesting grain and other produce, the Torah presents six different mitzvah opportunities to provide for the poor: leket, shich’cha, pei’ah, peret, oleilos, and maaser ani. I discussed several of these mitzvos in a recent article, but did not complete the topic. This article picks up where that one left off.

In parshas Kedoshim, the Torah mentions the mitzvos of pei’ah, leket, peret and oleilos: When you reap the harvest of your land, do not complete harvesting the corner of your field, and the “leket” of your harvest you should not collect. From your vineyard, do not remove the “oleilos,” and the “peret” of your vineyard you should not collect. Leave them for the poor and the stranger (Vayikra 19:9-10). I deliberately did not translate the words leket, oleilos and peret, since they will be explained shortly.

Shich’cha, peret and oleilos are all discussed at the end of parshas Ki Seitzei (Devarim 24:19-21).

Maaser ani is mentioned in parshas Ki Savo (Devarim 26:12)

Two of these mitzvos, pei’ah and leket, are also discussed in parshas Emor (Vayikra 23:22), in the midst of the Torah’s discussion about the festival cycle (parshas hamo’ados): When cutting the harvest of your land, do not complete the reaping of the corner of your field while you are harvesting, and the “leket” of your harvest you should not collect. Leave them for the poor and the stranger. This pasuk is the one included in our Sukkos reading.

Several halachos are quite clear from these pesukim, even without any commentary. The mitzvah is to leave behind these four items: pei’ah, leket, oleilos and peret, and allow the impoverished to help themselves. This implies that the owner may not choose or favor one pauper over another in the distribution of these gifts, and that neither he, nor anyone else, is even permitted to assist one poor person over another. To quote the Mishnah: He who does not allow the poor to collect, or allows one of them to collect but not another, or helps one of them, is stealing from the poor (Pei’ah 5:6).

Shich’cha

The mitzvah of shich’cha is discussed only at the end of parshas Ki Seitzei (Devarim 24:19): When you reap your harvest in your field, and you forget a sheaf in the field, you may not return to get it; it shall be for the stranger, the orphan and the widow, so that Hashem, your G-d, will bless you in all your undertakings. Shich’cha is different from the other four mitzvos we have previously mentioned in one significant way – it applies to produce only as it is brought in from the field, and not any earlier or later (Pei’ah 5:8).  Therefore, small bundles that were forgotten in the field, but where the intention, initially, was to combine them into larger bundles before bringing them in from the field, are not shich’cha (Pei’ah 5:8). This is different from the mitzvos of pei’ah, leket, peret and oleilos, which apply only at the time of the reaping, when the produce is being cut from the earth.

Shich’cha applies only when the owner or his workers forgot one or two bundles (Pei’ah 6:5). If they forgot three or more bundles, the law of shich’cha does not apply – the poor may not take it, and the owner may retrieve it.

Shich’cha applies only if we can assume that the sheaf or sheaves left behind are likely to be completely forgotten.  However, it does not apply if the owner or his worker will remember later that the bundle was left behind, for any of a variety of reasons, such as, it was left in a place that he will remember where it was, or it was much larger than the rest of his sheaves (Rambam, Hilchos Matanos Aniyim 5:17). Another example is when they forgot to harvest from a certain tree, but they will later remember about the tree because it is distinctive, either because it has its own nickname, or it is unusual in some other way or in its location (Pei’ah 7:1-2).

Shich’cha applies also to grapes, as well as to olives and the fruit of other trees (Pei’ah 6:9; 7:1).

What is leket?

To quote the Mishnah: What is leket? That which falls at the time of the cutting… If it is within [the reaper’s] hand or his sickle, it qualifies as leket and belongs to the poor. If it is beyond his hand or his sickle, it belongs to the owner and does not qualify as leket (Pei’ah 4:10). In other words, stalks of grain that were cut by swinging a sickle, but were beyond the hand or the sickle of the harvester, do not qualify as leket, because they were not severed from the ground in the way that grain is usually cut (Bartenura).

Three and over

The law of leket applies only when the reaper dropped one or two stalks at a time, but if he dropped three or more stalks, he may pick up the stalks and add them to his harvest, and the poor people are not permitted to take them (Pei’ah 6:5).

Piled on top of the leket

What is the halacha if the owner of the field or his employees collected the produce of his own harvest and then piled it in an area of the field where the poor people had not yet collected the leket. In this instance, we will no longer be able to ascertain how much leket grain in the field rightfully belongs to the poor, because the reapers’ pile creates a mixture of leket grain that belongs to the poor and non-leket grain that belongs to the owner.

To discourage this from happening, Chazal instituted that the entire bottom layer of the grain pile is considered the property of the poor (Pei’ah 5:1), even when it is impossible that so much grain fell as leket. This ruling is a penalty leveled upon the owner, to make sure that he does not allow such a practice. He should make sure that his workers pile their produce in an area that does not contain any leket.

What are peret and oleilos?

We have not yet explained the other two mitzvos that are taught in the pasuk that I quoted above, peret and oleilos. These two gifts to the poor exist only regarding grapes.

Peret is to a vineyard what leket is to grain. In other words, while picking the grapes, should a single grape or two fall from the hand of the harvester, they must be left for the poor (Pei’ah 6:5; 7:3). However, just as we explained before that three stalks of grain falling together while cutting are not leket, three of more grapes falling at one time are not peret and may be retrieved by the owner.

Oleilos

Oleilos are grapes that did not grow as part of a proper cluster. Ordinarily, a cluster of grapes includes many small bunches that grow off the main stem near the top of the cluster; when the grapes lie upon one another, they create a bulge, appearing a bit like a “shoulder,” near the top of the cluster. In addition, the central stem of typical cluster grows longer than the small bunches that branch off it, which causes some grapes to hang down at the bottom of the cluster. These two features provide a cluster of grapes with its traditional appearance of the widest part near, but not at, the very top, and the bottom being narrowest, where a few grapes hang lower than the rest of the cluster.

Oleilos are when a cluster of grapes grows without a “shoulder” at the top of the cluster and without any grapes of the main stem hanging lower than the rest of the cluster. A bunch of grapes growing without these features may not be harvested by the owner or his workers and is left for the poor (Pei’ah 7:4).

Maaser ani

Regarding maaser ani, the Torah states: When you complete all the tithes of your produce in the third year, the year of the special tithe, make certain to give it to the Levi, the stranger, the orphan and the widow, who will eat it within the gates of your cities and be satisfied (Devarim 26:12).

This pasuk alludes to at least two different tithes, and teaches that the third year has a tithe different from the previous years. In the third year, you must give one maaser, which we call maaser rishon, to the Levi, and a second maaser that is a maaser for the poor (the stranger, the orphan and the widow). This mitzvah, maaser ani, is mentioned also in parshas Re’eih (Devarim 14:28-29).

There is a fundamental difference between maaser ani and the other gifts to the poor. As mentioned above, gifts to the poor are left for them to help themselves. A more agile and industrious poor person can collect a great deal more leket, shich’cha, pei’ah, peret and oleilos than someone who has difficulty getting around. However, the pasuk in parshas Ki Savo states that the owner gives the maaser ani to the poor, meaning that he chooses which poor person will be the lucky recipient.

Answering questions

At this point, we have enough background that we can discuss one of our opening questions.  “I live in chutz la’aretz. Am I required to separate pei’ah on my backyard vegetable patch?” In other words, do any of these mitzvos of matanos la’aniyim apply outside Eretz Yisrael?

Matanos aniyim in chutz la’aretz

Although these mitzvos are halachically categorized as mitzvos hateluyos ba’aretz, agricultural mitzvos, and the general rule is that these mitzvos apply only in Eretz Yisrael (Mishnah Kiddushin 36b), the Gemara (Chullin 137b) mentions that the mitzvah of pei’ah applies in chutz la’aretz as a rabbinic injunction, and the Rambam explains that this includes all matanos aniyim (Hilchos Matanos Aniyim 1:14). We find this applies to several other of the mitzvos hateluyos ba’aretz, including challah, chodosh, terumos and maasros (because of space constraints, the details and definition of these different mitzvos will be discussed in other articles).

Regarding where in chutz la’aretz these mitzvos hateluyos ba’aretz are applied miderabbanan, there are two different sets of rules:

In the case of challah, the mitzvah applies anywhere in chutz la’aretz. Wherever you live, you are obligated to separate challah from a large enough dough.

Regarding terumos and maasros, the requirement to separate them applies only in lands near Eretz Yisrael – Mitzrayim, Amon, and Moav – corresponding to parts of contemporary Egypt, Jordan and the Sinai and Negev deserts. There is no requirement to separate terumos and maasros from produce grown in Europe, anywhere else in Africa, the vast majority of Asia, and certainly not from produce grown in the Americas or Australia.

The question at hand is whether the matanos aniyim have the same halacha that applies to terumos and maasros, and therefore they apply only in lands near Eretz Yisrael, or whether they are treated like challah and apply everywhere. Most authorities conclude that the obligation of matanos aniyim applies only in places near Eretz Yisrael.

At this point, let us focus on the first question that we posed: “Is there a requirement to leave leket, shich’cha and pei’ah in your field today?”

Answering this question correctly requires that we explain another principle. In the earlier article, I mentioned the Mishnah that states that if all of the poor people in a certain place want the pei’ah to be divided evenly among them, rather than being available for each to forage as he best can, the pei’ah is divided evenly among the local poor. We can ask a question: Granted that the local poor people all agree to divide the matanos aniyim equally, however, these gifts do not belong only to them. All poor people, no matter where they live, are entitled to these matanos. If so, how can the people here decide how to divide their local matanos aniyim, without taking into consideration the rights of poor people elsewhere, who are also potential owners of the matanos aniyim?

The answer is that the poor people who are outside this locale have clearly been me’ya’eish, implicitly given up their legal right to the local matanos aniyim (see Bava Metzia 21b). The poskim conclude that in any situation in which the owner can assume that the poor will not come to collect the matanos aniyim that are left in the field, he is permitted to collect and keep them (Derech Emunah, Hilchos Matanos Aniyim 1:62). Therefore, in today’s world where poor people are not traveling to fields to collect their matanos, there is no obligation to leave leket, shich’cha, pei’ah, peret and oleilos.

Conclusion

In our discussion of the mitzvah of shich’cha, we quoted the pasuk that states that someone who observes this mitzvah will have all his undertakings blessed by Hashem. Rashi (Vayikra 5:17) notes the extent of this blessing. After all, the person forgot only one sheaf, yet Hashem blesses all his undertakings. As Rashi expresses it: We see from here that if someone dropped a coin, and a poor person found it and supports himself with it, Hashem provides the loser of the coin with a beracha.

Question #1: Living in Chutz la’aretz

“I live in chutz la’aretz. Am I required to leave peah in my backyard vegetable patch?”

Question #2: Leaving in Today’s World

“Is there a requirement to leave leket, shich’cha and peah in your field today?”

Question #3: Cluster Alms

“Why is it important to know how a typical cluster of grapes looks?”

Introduction

While harvesting grain and other produce, the Torah presents six different mitzvah opportunities to provide for the poor: leket, shich’cha, peah, peret, oleilos, and maaser ani. These mitzvos, as well as many of the basic laws of the mitzvah of tzedakah, are discussed in the second mesechta of seder Zera’im, mesechta Peah, and in the commentaries thereon, including the Talmud Yerushalmi. As is the case with all the mitzvos hateluyos ba’aretz, the agricultural mitzvos of the Torah, there is no Talmud Bavli on Peah, although many of its topics are discussed, sometimes in great detail, in scattered places.

This article will provide a basic understanding of some of these six mitzvos and cover a few select details. In so doing, we will answer some of the questions asked above and leave the others for a future article.

Let us begin by quoting the pesukim that introduce these mitzvos. In parshas Kedoshim, the Torah mentions the mitzvos of peah, leket, peret and oleilos: When you reap the harvest of your land, do not complete harvesting the corner of your field, and the “leket” of your harvest you should not collect. From your vineyard, do not remove the “oleilos,” and the “peret” of your vineyard you should not collect. Leave them for the poor and the stranger (Vayikra 19:9-10).

I deliberately did not translate the words leket, oleilos and peret, since I will explain what these technical terms mean. Two of these mitzvos, peah and leket, are repeated in parshas Emor (Vayikra 23:22), in the midst of the Torah’s discussion about the festival cycle (parshas hamo’ados): When cutting the harvest of your land, do not complete the reaping of the corner of your field while you are harvesting, and the “leket” of your harvest you should not collect. Leave them for the poor and the stranger. In addition, the two mitzvos of peret and oleilos are again discussed at the end of parshas Ki Seitzei (Devorim 24:21), immediately following the Torah’s instructing the mitzvah of shich’cha. (We will quote the sources for the mitzvos of shich’cha and matanos aniyim later in this article.)

Several halachos are quite clear from these pesukim, even without any commentary. The mitzvah is to leave behind these four items: peah, leket, oleilos and peret and allow the impoverished to help themselves. This implies that the owner may not choose or favor one pauper over another in the distribution of these gifts, and that neither he, nor anyone else, is even permitted to assist one poor person over another. To quote the Mishnah: He who does not allow the poor to collect, or allows one of them to collect but not another, or helps one of them is stealing from the poor (Peah 5:6). This law applies equally to anyone, not only the field owner, who assists one poor person over another (see Peah 4:9).

Corner

At this point, we will explain the basics of the mitzvah of peah. The requirement of peah is to set aside a portion of your field that you do not harvest. There is no minimal requirement min haTorah regarding how large a section of the field must be designated as peah. In other words, the Torah’s mitzvah is fulfilled if someone sets aside only one stalk of grain. To quote the Mishnah: These items have no measured requirement: Peah, bikkurim, appearing in the Beis Hamikdosh on the festivals, performing kind deeds and studying Torah (Peah 1:1). This Mishnah is the basis for a halachic passage that we say every morning after we recite birkas haTorah, but what we say daily has other parts added to it from other statements of Chazal.

Why does the Mishnah mention only these five mitzvos? Are there no other mitzvos that have no “minimum amount” required in order to fulfill them?

Indeed, these are the only five mitzvos that fulfill the statement that they have no measured requirement, because min haTorah, these mitzvos have no minimum and also no maximum, whereas all other mitzvos have either a minimum or a maximum, min haTorah. The commentaries on this Mishnah raise questions about several other mitzvos that seemingly should be included in this list, making it more than five, and explain why each of these other mitzvos is not mentioned (Rash; Tosafos Yom Tov; Mishnah Rishonah).

Not all produce

Returning to the laws of peah, not everything that is grown must have peah separated from it. The Mishnah notes that only produce that has five specific characteristics is included in the mitzvah of peah. To quote the Mishnah: They (the earlier authorities) stated a rule regarding peah. Anything that (1) is food, (2) is guarded, (3) is nourished from the ground, (4) is reaped at one time, and (5) is brought in for long-term storage is obligated in peah. Grain and legumes are always assumed to be included (Peah 1:4).

In other words, the following categories of produce are exempt from peah:

(1) Products grown for feed or for dyestuffs (such as woad or indigo).

(2) Produce that is hefker, meaning that it is evident that the owner has no concern if other people take it.

(3) Cultivated mushrooms, truffles, and other fungi, because they do not draw their nourishment from the ground.

(4) Some varieties of produce do not ripen all at once. Instead, they are harvested in stages, as each fruit ripens. These types of products, such as figs, are exempt from the mitzvah of peah.

(5) Many varieties of vegetables and other produce cannot be stored unless they are frozen or canned. Any of these types of produce are exempt from peah. However, items that can be dried or stored as is, such as grain, beans, peas, carobs, nuts, grapes (can be stored either as wine or as raisins), olives (as oil) or dates (dried) are obligated in peah.

How much peah?

Earlier, we quoted the Mishnah that ruled that the Torah requirement of the mitzvah of peah has no minimum size. The Mishnah subsequently teaches that although the Torah did not require a minimum to fulfill this mitzvah, Chazal did, enacting a rule requiring the owner to set aside at least 1/60 of his field as peah. Furthermore, he is required to set aside a larger part than this for peah under some special circumstances, such as, he had a bumper crop, he is exceptionally wealthy, there are a lot of poor or the impoverished are exceptionally needy (Peah 1:2 according to various commentaries).

Corner

Must peah be in a corner of the field?

Notwithstanding that the Torah calls the mitzvah peah, and that, in the context of other mitzvos of the Torah, the word peah means a corner of some type, it is not required to set aside peah in a corner of the field, nor does it necessarily have to be set aside when the harvest is finished. In addition, at the beginning of the harvest, the owner may designate a part of his field as peah. To quote the Mishnah: You can give peah from the beginning of the field or from its middle (Peah 1:3).

Three times a day, the owner must appear at his field to allow the poor to collect what they are entitled (Peah 4:5). The three times of the day are in the morning, at midday and towards the late part of the afternoon. There appears to be a dispute among halachic authorities exactly what this Mishnah is ruling. According to some authorities, the poor may not enter the field unless the owner, or his representative, is there, but the owner is required to be there at these three times, or otherwise appoint a representative in his stead, who will be in the field these three times every harvest day (Rashas; Mishnah Rishonah).

The Rambam appears to understand the Mishnah and the halacha somewhat differently: The poor may not enter the field at any other time, but during these three times they are free to enter, whether or not the owner or his representative are there (Hilchos Matanos Aniyim 2:17). In his opinion, the Mishnah should be understood as follows: “Three times a day the pauper may appear at the field.”

Nobody get hurt!

The halacha is that the poor people reaping the peah may not use sickles or spades to gain access to the leftover produce. Since many poor people are in the field, and they are not coordinating their activities, using a heavy tool could cause someone to get hurt (Peah 4:4).

Exceptional distributions

As noted above, peah and the other matanos aniyim that we have so far discussed should be left for the poor to take for themselves. However, there are exceptions:

(1) Something that is dangerous for the poor to harvest themselves. The Mishnah (Peah 4:1) chooses two examples of fruit — dates and grapes growing on trellises — where it might be dangerous for the poor to harvest the peah themselves (Rosh, Rav and Rashas ad loc.). Dates grow only on the new growth of a date palm. Since the dates will be only on the top of the tree and a palm tree can grow quite tall, it could certainly endanger the poor people, should they have to harvest the dates themselves.

Similarly, grapes grow on vines which are basically runners, rather than strong trees. To maximize the quantity and quality of their crop, it is common that vinedressers (people who cultivate grapevines) construct wooden frames called trellises, looking something like a jungle gym, and train the grape vines, which are very easy to educate, to grow on these trellises. However, it is not safe to allow the poor people to come collecting the peret grapes by themselves from trellises. Numerous poor people may attempt simultaneously to collect the grapes left on a trellis, and a trellis may not be strong enough to hold their collective weight.

To avoid people endangering themselves, in these instances the harvester cuts down the peah fruit and distributes what is there evenly among the poor who have assembled (Peah 4:1).

(2) A second case where the owner should harvest and distribute the produce is when all of the poor people who have arrived at the field want it divided evenly (Peah 4:2).

Maaser ani

Maaser ani is mentioned in parshas Ki Savo, where the Torah states: When you complete the tithing of all the tithes of your produce in the third year, the year of the special tithe, then you shall make certain to give it to the Levi, the stranger, to the orphan and the widow, and they shall eat it within the gates of your cities and be satisfied (Devorim 26:12).

This posuk talks about creating at least two different tithes, and mentions that the third year has a special tithe that the earlier years do not have. In the third year, you must then give one maaser to the Levi, which we call maaser rishon, and a second maaser to the stranger, orphan or widow, which is clearly meant to be a maaser for the poor. This mitzvah of maaser ani is also mentioned in an indirect way, in parshas Re’eih (Devorim 14:28-29).

Thus, there is a fundamental difference between maaser ani and the other gifts to the poor in that, in general, the others are left for the poor people to help themselves. In other words, a poor person who is more agile and willing to work hard can collect a great deal more leket, shich’cha, peah, peret and oleilos then someone who has difficulty getting around. However, the posuk in parshas Ki Savo states that the owner gives the maaser ani to the poor. This implies that he can choose which poor person he wants to provide. In general, it is his to distribute to the poor, as he chooses.

Answering questions

At this point, we have enough background to the general laws of these mitzvos that we can return to of our opening questions.  The first question was: “I live in chutz la’aretz. Am I required to separate peah on my backyard vegetable patch?”

In other words, do any of these mitzvos of matanos la’aniyim apply outside Eretz Yisroel?

Matanos aniyim in chutz la’aretz

Although these mitzvos are halachically categorized as mitzvos hateluyos ba’aretz, agricultural mitzvos, and the general rule is that these mitzvos apply only in Eretz Yisroel (Mishnah Kiddushin 36b), the Gemara (Chullin 137b) mentions that the mitzvah of peah applies in chutz la’aretz as a rabbinic injunction, and the Rambam explains that this includes all matanos aniyim (Hilchos Matanos Aniyim 1:14). We find this applies to several other of the mitzvos hateluyos ba’aretz, including challah, chodosh, terumos and maasros (because of space constraints, the details and definition of these different mitzvos will be left for other articles).

However, this does not yet resolve our question; regarding rabbinic injunctions germane to mitzvos hateluyos ba’aretz that are extended to chutz la’aretz, we find two different sets of rules:

In the case of challah, the mitzvah is applied to anywhere in chutz la’aretz. This is why, no matter where you live, you are obligated to separate challah from a large enough dough.

On the other hand, in the case of terumos and maasros, the requirement to separate them in chutz la’aretz applies only in lands near Eretz Yisroel, such as Mitzrayim, Amon, and Moav – today corresponding to parts of Egypt, Jordan and the Sinai and Negev deserts. There is no requirement to separate terumos and maasros from produce grown in Europe, anywhere else in Africa, the vast majority of Asia, and certainly not from produce grown in the Americas or Australia. (Which rule applies to chodosh is a topic for a different time.)

The question at hand is whether the matanos aniyim have the same halacha that applies to terumos and maasros, and therefore they apply only in lands near Eretz Yisroel, or whether they are treated like challah and apply everywhere. Most authorities conclude that the obligation of matanos aniyim applies only in places near Eretz Yisroel.

At this point, let us focus on the other question that we posed: “Is there a requirement to leave leket, shich’cha and peah in your field, today?”

Answering this question correctly requires that we explain another principle. Above I mentioned the Mishnah that states that if all of the poor people in a certain place want the peah to be divided evenly among them, rather than being available for each to forage as best he can, indeed the peah is divided evenly among the local poor. We can ask a question: Granted that the local poor people all agree to divide the matanos aniyim equally, however, these gifts do not belong only to them. All poor people, no matter where they live, are entitled to these matanos. If so, how can the locals decide to divide among themselves the matanos aniyim without taking into consideration the rights of those elsewhere, who are also potential owners of the matanos aniyim?

The answer is that the poor people who are not here have clearly been me’ya’eish, implicitly given up their legal right to the matanos aniyim that are here (see Bava Metzia 21b). The poskim conclude that any situation in which the owner can assume that the poor will not come to collect the matanos aniyim that are left in the field, he is permitted to collect them (Derech Emunah, Hilchos Matanos Aniyim 1:62).

Conclusion

In the days of King Munbaz there was a drought, and he distributed the entire royal treasury, accumulated over several generations, to the poor. His family members protested, saying that his predecessors had all increased the wealth of the monarchy, and Munbaz was disbursing it. Munbaz responded, “My ancestors stored below, and I stored above. They stored their wealth in a place where it could be stolen, and I stored in a place from where it cannot be stolen. They stored items that do not produce profits and I stored items that do. They stored money, and I stored lives. They stored for others, and I stored for myself” (Bava Basra 11a).

Question #1: Spelt

I understand that spelt is a type of wheat. May I plant a small patch of it next to my wheat field?

Question #2: Trees and Ornamentals

I purchased a property in Israel that has grapes and other trees and ornamentals growing on it. What do I do to avoid violating the prohibition of kil’ayim?

Question #3: Tomatoes

May I plant various types of tomatoes next to one another?

Foreword:

In parshas Ki Seitzei, the Torah teaches the mitzvah not to plant your vineyard with kil’ayim (Devarim 22:9), after which the Torah mentions two other kil’ayim prohibitions: doing work with different animal species together and wearing shatnez. In parshas Kedoshim, the Torah introduces several mitzvos called kil’ayim when it says, “You shall keep my laws. You shall not breed your animals as kil’ayim, you shall not plant your field as kil’ayim and you shall not wear kil’ayim shatnez garments” (Vayikra 19:19).

I have written many times about the prohibitions of wearing shatnez, grafting one tree min (species) onto another and crossbreeding animals, but I have never written an article devoted to this week’s topic — the kil’ayim prohibitions in a vineyard and in a field. Please note that this article is only a general introduction to these mitzvos and not halacha le’maaseh — the topics are far more complex than can be covered in one article. For this reason, the opening questions in this article are going to be left unanswered.

Kil’ei hakerem

Kil’ei hakerem is the prohibition of planting an herbaceous (meaning non-woody, i.e.  – a plant other than a trees or a shrub), cultivated plant in a vineyard or adjacent to a grapevine. This mitzvah applies min haTorah in Eretz Yisrael and as a rabbinic prohibition in chutz la’aretz (Orlah 3:9; Kiddushin 39a). It also includes planting above or below grapes, such as, if the vine is trained onto a trellis or other framework.

Kil’ei hakerem is the only instance in which the Torah prohibits using what grows in violation of the kil’ayim prohibition. Other kil’ayim mitzvos prohibit only the act, but what grows or develops as a result may be used. (The Yerushalmi, Kil’ayim 1:4, permits using even the cutting developed from a forbidden graft.)

There is a major dispute among tana’im and rishonim whether kil’ei hakerem applies even when planting one species other than grapes in a vineyard, or only when two species other than the grapes are planted in a vineyard. Rav Yoshiyah rules that the lo sa’aseh of kil’ei hakerem applies only when planting both wheat and barley (or any two other species that are kil’ayim with one another) in a vineyard. Since the Torah says, “You shall not plant kil’ayim in your vineyard,” Rav Yoshiyah understands this to mean that someone is planting two varieties that are kil’ayim with each other, in a vineyard, which compounds the prohibition.

Vineyard vs. vines

There are major halachic differences between a few grapevines and what is halachically called a vineyard. The most prominent difference is that it is prohibited to plant any type of grain or most vegetables within four amos (about seven feet) of a vineyard, whereas it is forbidden to plant only within six tefachim, which is less than two feet, of a grapevine that is not part of a vineyard.

What is a vineyard?

So, what is a vineyard?

The halacha is that a vineyard must have at least five grapevines growing, four of which are positioned in a rectangle or square. Exactly how the fifth vine is planted is unclear from the Mishnah (Kil’ayim 4:6), and is disputed by the halachic authorities. The Chazon Ish rules that a vineyard requires that the fifth vine continues in a straight line from two of the other vines. In other words, the minimum definition of a vineyard is two parallel grape plantings, one of at least three plantings and the other of at least two.

Others contend that the fifth vine can also be similar to the way one would envision, from a bird’s eye view, the location of the tail relative to the four legs of an animal standing in rapt attention. The four legs form a rectangle, and the tail is alongside the rectangle, but opposite the middle of a side rather than the continuation of one of its sides (Rambam, Peirush Mishnayos, Kil’ayim 4:6; Tosafos Yom Tov; cf., however, Rambam, Hilchos Kil’ayim 7:7).

If five vines have been planted this way, and alongside them many more vines were planted haphazardly, the disorganized vines might not be considered a vineyard, but individual vines. The practical difference is whether vegetables and grains may be planted nearby, as long as they are more than six tefachim from the vines, or whether the laws of a vineyard apply, which requires a much more substantive distance of four amos. In both instances, construction of a tzuras hapesach or other mechitzah will allow planting the vegetables or grains alongside the vines, as long as the mechitzah separates between the vines and the vegetables or grains.

One row of grapevines is not considered a vineyard, even if it contains hundreds of plantings (Kil’ayim 4:5). This means that one may plant vegetables or grains alongside the grapes, as long as there is a six tefachim distance between them.

Kil’ei hakerem in chutz la’aretz

The rules of kil-ei hakerem in Eretz Yisrael are stricter than they are in chutz la’aretz. In chutz la’aretz, there is a rule, kol hameikil ba’aretz, halacha kemoso bechutz la’aretz. For our purposes, this rule means that since the law of kil’ei hakerem in chutz la’aretz is only miderabbanan, Chazal ruled that whenever a recognized scholar ruled that a particular situation is not considered kil’ayim in Eretz Yisrael, even when the halachic conclusion rules against him, one may follow this minority position in chutz la’aretz. For example, since Rav Yoshiyah rules that kil’ei hakerem is prohibited only when planting two species (that are already prohibited together) in a vineyard, this is the only act of kil’ei hakerem prohibited in chutz la’aretz. However, in Eretz Yisrael, there is concern over planting even a single type of vegetable in a vineyard.

Kil’ei zera’im

Kil’ei hasadeh or kil’ei zera’im (two ways of referring to the same prohibition) is planting two non-woody (also called “herbaceous”) commonly cultivated plants or seeds near one another, planting one species very close to another, already-planted species, or planting the seeds of one species on top or inside a specimen of another species. This mitzvah applies only in Eretz Yisrael. In chutz la’aretz, it is permitted to plant two herbaceous plants next to one another, although some authorities prohibit planting the seed of one species on top of or inside another in chutz la’aretz (Rambam, Hilchos Kil’ayim 1:5; Tosafos Chullin 60a s.v. Hirkiv). Therefore, in Eretz Yisrael, someone planting a garden patch must be very careful to keep the different species separate.

Both prohibitions, kil’ei hakerem and kil’ei zera’im exist, even if the species are not intentionally planted together, but grew on their own (Kil’ayim 2:5). In this instance, if the two species are too close together, one either must pull out one, or, as we will see shortly, build a mechitzah between them.

Introductions

Several important introductions will facilitate understanding the laws of these mitzvos.

A. Firstly, many assume that kil’ayim prohibits hybridization or crossbreeding (two ways of saying the same thing) of unlike species, or, in simpler terms, attempting to mix genetic material and create new species. However, this approach is inaccurate, since only one of the many kil’ayim prohibitions, crossbreeding animals, attempts to create something that does not occur in nature. All the other mitzvos ban the appearance of mixing two species. This distinction is very important in understanding many of the laws of kil’ayim.

B. Secondly, for clarity’s sake, I will use the word “species” in this article to mean items that halacha prohibits “mixing.” The dictionary definition of the word “species” is “a pool of individuals that breed together and will not breed with other individuals.” However, neither halacha nor science uses this definition. Since this article is a halachic talk about kil’ayim, I will discuss only aspects of the halachic definition germane to these mitzvos.

What defines a halachic species? Although there is a great degree of uncertainty about this, certain principles can be derived from the various passages, particularly of the Talmud Yerushalmi Kil’ayim.

(1) Two varieties that naturally cross-pollinate are halachically considered one species (see Yerushalmi Kil’ayim 1:2).

(2) At times, similarity of leaves or appearance or taste of the fruit are sufficient evidence to consider two varieties as members of the same species (Yerushalmi Kil’ayim 1:5). Small differences are never considered significant (Bava Kama 55a). Thus, different varieties, one of which grows wild and the other of which is cultivated, are usually one species (Mishnah Kil’ayim 1:2). Frequently, the rules are difficult to define and, therefore, most authorities recommend not growing two similar varieties of squash or beans together.

C. It is also important to note that the definition of “species” for the laws of kil’ayim is not the same as it is for the laws of challah. Spelt and wheat are considered different minim for the laws of kil’ayim, notwithstanding that they are the same min for the laws of challah. (This means that dough made of spelt and wheat flour can combine to create enough dough to be obligated to separate challah, notwithstanding that wheat and spelt cannot be planted next to each other.)

Cultivated

D. As I mentioned above, kil’ei zera’im and kil’ei hakerem apply only to species that are cultivated or maintained in your location for food, forage, clothing, dye or other similar purposes. The Mishnah states that the laws of kil’ayim apply to a species called zunin,usually understood to be darnel, a ryegrass that, in earlier generations, was used as bird seed. Planting zunin in a field of barley, rye, oats or spelt violates the prohibition of kil’ei zera’im. (Why it is permitted to plant zunin in a wheat field [Mishnah Kil’ayim 1:1] is a topic that we will leave for a different time.)

Proximity

Planting two crop species together or near one another is prohibited as kil’ayim. How far apart the two species must be depends on several factors, including the layout of the planting and what and how much was planted. In some situations, when growing small amounts of certain vegetables, planting the two species in alternate patterns is sufficient to permit the planting, notwithstanding that the different species grow alongside one another (Kil’ayim 3:1; Shabbos 84b ff.).

Between two grain fields of different species — for example, one growing spelt and the other rye — there needs to be an empty area greater than ten amos squared, approximately twenty feet by twenty feet, between the two fields. On the other hand, between two kinds of vegetables, the requirement is that the separating area be only six tefachim squared, approximately two feet by two feet. And even the size of this requirement is only miderabbanan. Min haTorah there is a dispute among rishonim whether the distance is one tefach squared, or 1.5 tefachim squared (Raavad, Hilchos Kil’ayim). The Chazon Ish (5:1) ruled according to the Rambam, the lenient opinion, that requires only one tefach squared, approximately four inches by four inches.

Mechitzah

Although we usually think of mechitzah as a separation necessary in a shul, the word has significance in several other areas of halacha, and particularly in the laws of kil’ayim. For the purposes of kil’ayim, whenever one wants to plant two species and there is not enough space to allow this, a halachically acceptable separation between the plantings permits the planting (Kil’ayim 2:8; 4:6). The rules here are similar to what is called a mechitzah for other halachos, including permitting carrying on Shabbos, although, for the laws of Shabbos, the entire area must be enclosed by mechitzos on all sides. For the laws of kil’ayim, it suffices that there is a halachic divider separating the plantings from one another. Among the many ways that someone can separate the two areas is by building a wall that is ten tefachim tall (approximately 32-40 inches) or piling rocks to a height of ten tefachim. Another option is a furrow or crevice in the ground, either natural or dug, that is ten tefachim deep.

The Mishnah (Kil’ayim 4:4) notes that lavud, openings that are smaller than three tefachim (about ten inches), does not invalidate a mechitzah, and therefore a fence that is more open than closed, but is ten tefachim tall, is a valid mechitzah for kil’ayim purposes. Similarly, one may build a “wall” with sticks placed either horizontally or vertically every three tefachim, and it is a satisfactory mechitzah.

This means that someone may have a vineyard on one side of a fence, in which the grapes grow alongside the fence, and plant grain or vegetables on the other side of the fence; it is completely permitted, even though the two crops may be growing within inches of one another.

Gaps

Large gaps in the middle of a mechitzah may not invalidate it. The general halachic principle is that an area that is mostly enclosed is considered “walled,” even in its breached areas (Kil’ayim 4:4; Eruvin 5b). For example, a yard enclosed by hedges tall enough to qualify as halachic walls may be considered enclosed, notwithstanding that there are open areas between the hedges, since each side is predominantly enclosed either by the hedges or by the house. This is true as long as the breach is smaller than ten amos,about 17 feet (Kil’ayim 4:4). This means that someone may have a vineyard on one side of the hedges (inedible growths usually do not create prohibited kil’ayim), and grain or vegetables on the other side of the hedges, even though the two crops may be extremely close to one another.

Tzuras hapesach

The Gemara (Eruvin 11a) rules that a tzuras hapesach, which we customarily use to make to enclose an area to permit carrying on Shabbos, may be used to separate two species, so that there is no prohibition of kil’ayim. A tzuras hapesach consists of two vertical side posts and a horizontal “lintel” that, together, vaguely resemble a doorway. Thus, it is permitted to grow a vineyard on one side of the tzuras hapesach and grain or vegetables on the other side.

Weeding

What about weeds? Do weeds present a kil’ayim concern?

As anyone who gardens knows, the definition of a “weed” is whatever the gardener does not want in his garden. Halachically, if the “weed” is from a species that is not maintained in your area, it is not a kil’ayim concern.

Conclusion

Targum Onkelos (Vayikra 19:19 and Devarim 22:9) understands the word kil’ayim to mean “mixture.” However, other commentaries explain the origin of the word from the Hebrew root כלא, the same as the word beis ke’le “prison” (see Bamidbar 11:28). Rav Hirsch (Vayikra 19:19) explains that the root כלא means to hold something back, and that the plural form kil’ayim — similar to yadayim, hands, or raglayim, feet — means a pair. Therefore, the word kil’ayim means to pair together two items that should be kept apart.

Concerning this, Rav Hirsch (Vayikra 19:19) writes, “The Great Lawgiver of the world separates the countless numbers of His creations in all their manifold diversity, and assigns to each one of them a separate purpose and a separate form for its purpose.”

In addition, observing the laws of kil’ayim helps us remember how various species obeyed Hashem’s instructions to remain separate during their creation. This reminds the contemplative Jew that if the plants heeded Hashem’s word during the Creation, how much more are we obligated to obey His instructions!

Question #1: Wolf and Dog

Are wolves and dogs members of the same species?

Question #2: Bactrian and Dromedary

May I haul a wagon with two camels, a Bactrian and a dromedary?

Question #3: Tangelo

Is it permitted to crossbreed tangerine and grapefruit to create a tangelo?

Question #4: Crabapples

May I graft an apple branch onto a crabapple trunk?

Foreword:

At the beginning of parshas Noach, Rashi teaches us that, during the moral chaos that led to the Mabul, even members of the animal kingdom mated outside their species (min), something that no self-respecting and ethical animal would ever do.

At this point, we need to ask what is meant by min, which is usually translated as species. The dictionary definition of the word “species” is a pool of individuals that can breed together and do not breed with other individuals.

However, we will soon see that neither halacha nor science uses this definition. It is important that, when studying the Talmudic, aggadic and halachic topics germane to kil’ayim, we must understand properly the Torah’s meaning of the term “species.”

Crossbreeding

Many halachically knowledgeable people assume that the purpose of the laws of kil’ayim is to prohibit the hybridization or crossbreeding (two ways of saying the same thing) of unlike species, or, in simpler terms, not to attempt creating new biological species or to mix genetic material of different species. However, we will soon demonstrate that this assumption is specious, since it is inconsistent with halachic accuracy for two completely different reasons:

A. Most kil’ayim prohibitions have nothing to do with creating new species.

B. In numerous instances, the laws of kil’ayim permit mingling two varieties that are biologically different species, and there are situations in which the laws of kil’ayim prohibit mingling two varieties that are biologically considered members of the same species.

Types of kil’ayim

First, we will demonstrate that kil’ayim prohibitions rarely have anything to do with creating new species (point A). Mesechta Kil’ayim deals with six different mitzvos involving the intermingling of species:

1. Crossbreeding animal species. This prohibition is called harva’as beheimah, or sometimes simply harva’ah. In this instance, as in most of the cases of kil’ayim, there is no prohibition against using the product created by someone who violated the prohibition. Thus, it is permitted to use a mule, notwithstanding that mating a donkey with a mare to produce a mule violates a lo sa’aseh min haTorah.

2. Using two animal species to haul or work together. This mitzvah is usually called lo sacharosh, as in the words of the Torah: lo sacharosh beshor uvachamor yachdav,“Do not plow with an ox and a donkey together” (Devarim 22:10).

3. Grafting different tree species, harkavas ilan, which prohibits inserting a shoot or scion of one species into the wood stock, or lower trunk, of another species. Note that it is completely permitted to plant different species of trees next to each other (Yerushalmi, Peah 1:4).

4. Planting a non-woody edible plant, such as a vegetable or grain, in a vineyard. (A “non-woody” or “herbaceous” plant is a plant other than a tree or a shrub.) This prohibition is called kil’ei hakerem, and applies min haTorah only in Eretz Yisrael, although it does apply in chutz la’aretz as a rabbinic prohibition. This mitzvah is atypical in that it is the only prohibition of kil’ayim whose product is prohibited to use, min haTorah.

5. Planting two non-woody edible plants near one another. This mitzvah, called kil’ei hasadeh, kil’ayim of the field, applies only in Eretz Yisrael. In chutz la’aretz it is permitted to plant two herbaceous plants next to one another.

6. Wearing shatnez, clothing that includes both wool and linen. The prohibition is limited to wearing such clothing.

The two mitzvos of kil’ei hakerem and kil’ei hasadeh, apply min haTorah only in Eretz Yisrael, whereas the others apply min haTorah both in Eretz Yisrael and in chutz la’aretz.

I stated above that kil’ayim prohibitions usually have little or nothing to do with the creation of new species. Crossbreeding of plants involves pollinating the flower of one species with pollen from a different species. But none of the agricultural mitzvos listed above has anything to do with hybridization.

Let’s take a more careful look at the three agricultural prohibitions: 3, 4, and 5, above. In the cases of herbaceous, or non-woody, plants, kil’ayim is planting two crop species near one another (#5) or planting them inside a vineyard (#4). But planting the seeds of different species in close proximity does not change the DNA of the species or cause any hybridization, nor does it cause anything to grow of a variety different from either parent.

In the case of trees and shrubs, harkavas ilan (#3) means grafting one species onto another. When you graft a branch of one species onto the stock of another, the fruit that grows has the DNA of the scion branch and no DNA material of the species of the stock.

Also note that these three kil’ayim prohibitions are limited to species in which some part of the plant is edible.

Wool and linen

Wearing a garment that contains both wool and linen (#6) does not cause any hybridization. Wool grows on sheep, and linen is the product of a flax plant. Combining the two textiles in a garment does not affect their genetic material.

Lo sacharosh

Although some wish to explain that the prohibition of using two animal species to haul or otherwise be worked together is out of concern that someone will house them together or otherwise cause them to mate (Alshich, Devarim 23), there are many other ways to explain the “reason” for this prohibition (see, for example, Ibn Ezra, Devarim 22:10).

Harva’as Beheimah

The only one of the six kil’ayim prohibitions that involves hybridization is harva’as beheimah. But I presume that my readers agree that it is very strange to provide a reason for six different mitzvos that does not apply to five, or, possibly, not to four of them!

And, although we usually translate the word kil’ayim as “mixture,” some commentaries associate this word with the root כלא, as in the word “prison,” beis ke’le. Rav Hirsch explains the root word ke’le as holding something back, keeping someone incarcerated. The plural form kil’ayim is structurally similar to yadayim, raglayim or kesafayim,and means “a pair.” Thus, the word kil’ayim means pairing together items that should be kept apart (Hirsch Commentary to Vayikra 19:19), a definition that fits all six categories of kil’ayim, but has nothing to do with hybridization.

Dogs and wolves

My second point above (point B) is that there are numerous instances where the laws of kil’ayim permit mingling two kinds that are biologically considered different species, and there are also many instances in which the laws of kil’ayim prohibit mingling two kinds that are biologically considered the same species.

To explain, I will first pick examples in the animal world and then in the plant world. The Mishnah (Kil’ayim 1:6) states that wolves and dogs are kil’ayim together; it is forbidden to crossbreed them or to have them haul a load together. Yet, wolves and dogs breed together freely in the wild. Thus, we see that kil’ayim is not dependent on whether the varieties breed together.

From the Yerushalmi and the halachic authorities it appears that several factors are used to determine whether two varieties are considered different species, including how mankind views them, as the Torah teaches, “Hashem had created… all the animals of the field and the birds of the sky and He brought them to the man to see what he would call them… And the man gave names to all the domesticated animals and the birds of the sky and the animals of the field (Bereishis 2:19-20). This implies that man understood the purpose or uniqueness of each species and how it should be categorized, separately, from all other species.

Scientific dogs

The scientific system for classifying species, developed by Carl Linnaeus in the eighteenth century, names every species by two words: the first, its genus, which is capitalized, and the second, a lower case word for its species. Occasionally, a third word, also lower case, is added to indicate subspecies, which can also be called race, ethnic group, breed, variety or cultivar. (Humans are divided into races and ethnic groups, dogs into breeds, fruits and vegetables into varieties – or cultivars for boutique products.) Linnaeus categorized dogs as Canis familiaris and wolves as Canis lupus,meaning that he considered them two separate species. Today, most scientists categorize domesticated dogs as Canis lupus familiaris, which means that Canis lupus refers to a single species that includes both wolves and dogs, and familiaris is added for any domesticated dog breed.

An interesting comparison can be made with the dingo, a non-domesticated Australian dog. I checked Wikipedia regarding the dingo’s classification, and found the following: “The dingo, Canis familiaris, Canis familiaris dingo, Canis dingo, or Canis lupus dingo, is an ancient lineage of dog found in Australia. Its taxonomic classification is debated, as indicated by the variety of scientific names presently applied in different publications. It is variously considered a form of domestic dog not warranting recognition as a subspecies (Canis familiaris), a subspecies of either dog or wolf (Canis familiaris dingo or Canis lupus dingo), or a full species in its own right (Canis dingo).” I note that Wikipedia assumes that wolves and dogs are considered separate species.

The contemporary scientific world no longer defines a species by its ability to breed together and not to breed with a different species. As contemporary science has reinvented itself in the modern world, including its widespread misconceptions of spontaneous evolution of species and its unproved hypotheses regarding the origin of species, it can no longer use the definitions of breeds as its basis for defining species. This is because it accepts that species eventually mutate naturally into new species, which rejects or modifies the traditional definition of a species breeding within itself. As a result, science is forced to redefine “species” on the basis of similarity of DNA, but this piece of information has as yet not been communicated to the dictionary editors.

Camels

I have just demonstrated where, halachically, something can be considered two different species, notwithstanding that they breed together. I will now pick an example in which halacha considers two varieties to be the same species, notwithstanding that modern science categorizes them as separate species. The Gemara teaches that the one-humped Arabian camel, the dromedary, and the two-humped Bactrian camel (“Persian camel,” in Chazal’s lexicon) are, without question, one species. (By the way, “Bactria” was an area of ancient Persia; thus, Chazal’s method of distinguishing between the two varieties of camel is identical to modern nomenclature.) The Gemara states, rhetorically: “do you consider them different species, simply because one variety has a longer neck?” (Bava Kama 55a). Obviously, minor differences in physical characteristics are insufficient reason to treat two varieties as halachically different species.

Modern science counts three surviving species of camel, and, based on fossil remains, five extinct species. (How can one tell whether two extinct individuals could breed together or not?) The three existent species are Camelus dromedarius, the one-humped Arabian camel; Camelus bactrianus, the two-humped, domesticated variety; and Camelus ferus, the only remaining variety of wild camel, which lives today in desert areas of northwestern China and southwestern Mongolia. Formally, scientists will tell you that Camelus ferus is considered a separate species on the basis of genetic studies. Informally, they may admit that it is categorized as a separate species in order to facilitate research grants. Research money is more readily available to study “species” that are critically endangered than critically endangered “subspecies.”

Spelt wheat

Thus far, I have demonstrated that, in the animal world, halacha’s category “min,” and modern science’s nomenclature “species” do not necessarily coincide. Now, I will show that this is equally true in the plant world. Modern science does not consider wheat to be a species, but to be a genus, a group of related species, Triticum. Linnaeus categorized wheat into five different species, including spring wheat, winter wheat, Einkorn, and spelt as separate species. However, halacha recognizes spelt as one species and the other varieties as different forms of the species, wheat (Kil’ayim 1:1, see Rash and Rambam). Thus, it is permitted to plant different wheats together, or alongside one another, even in Eretz Yisrael, whereas one may not plant wheat and spelt together or alongside one another, without following the rules established for kil’ayim of two different species.

Citrus

Science treats the various citrus fruits as species of the same genus. Thus, esrogim are Citrus medica; grapefruits, Citrus paradise; lemons, Citrus limonia;and tangerines are a varietyof Citrus nobilis called Citrus nobilis deliciosa. Yet, based on his extensive analysis of halachic sources, the Chazon Ish (Kil’ayim 3:7) considers lemons, esrogim, grapefruits and oranges to be the same species as regards the laws of kil’ayim, which would permit grafting a grapefruit tree onto a lemon stock. (However, in a different place, the Chazon Ish is hesitant about this decision and rules against relying on it [Hilchos Kil’ei Ilan 178:9]. His concern in the latter place is the difference in appearance of the various fruits. He also rules that chushchash, a variety of wild orange, and the oranges that we eat and juice are the same min for halachic purposes [Hilchos Kil’ei Ilan 178:11].) The Chazon Ish notes that his discussion is germane only to the prohibition regarding harkavas ilan, meaning that it is permitted to graft an esrog branch onto the stock of a different citrus for the objective of consuming the produce. However, an esrog grown this way will not be kosher to use as one of the four minim on Sukkos. (See Shu’t Rema #117; #126:2; Shu’t Maharam Alshich #110; Levush, Orach Chayim 649:4; Taz and Magen Avraham, Orach Chayim 649; Shu’t Bach #135 et al., all of whom agree that an esrog grafted onto a different species is not kosher for Sukkos use. The Shu’t Panim Me’iros, Volume II #173, and the Saba Kadisha,are among the small minority of authorities who permitted using an esrog grafted onto non-esrog stock for the four minim on Sukkos.) In other words, according to most authorities, an esrog grafted on lemon stock is not kosher for the mitzvah on Sukkos, notwithstanding that the grafter may not have violated any prohibition.

Tangelo

We can now discuss the third of our opening questions: “May I create a tangelo by crossbreeding a tangerine and a grapefruit?” Although the Chazon Ish did not discuss tangerines, it would seem that, according to his comments in Kil’ayim 3:7, this would be permitted, and that, according to his comments to Yoreh Deah, it would not.

Crabapples

At this point, we should examine the last of our opening questions: May I graft an apple branch onto a crabapple trunk?

The regular eating-apple is usually called Malus pumila. There are numerous varieties of crabapples, most of which are also included in the genus Malus and are called names such as Malus coronaria, Malus angustifolia and Malus ioensis. Many of these crabapples freely hybridize in the wild with apple cultivars. Thus, we see again that the dictionary definition of a species is no longer accepted by the scientific community.

What is the halacha of grafting apples onto crabapple stocks?

The Mishnah states that apples are kil’ayim with chazrad, some type of wild apple or other fruit bearing some resemblance to, or characteristics, of an apple. Some rishonim believe that chazrad is a variety of wild apple that produced a fruit that was used as feed, but was not considered suitable for human consumption, even after pickling or stewing. However, we do not really have any idea what species or variety chazrad is.

In early nineteenth-century eastern and central Europe, we suddenly find several major halachic authorities debating whether some variety of crabapple or wild apple could be used as the stock on which to graft edible apple trees. The crabapple fruits were usually not considered edible.

The Torah scholar who addressed this question to the author of Shu’t Mishkenos Yaakov considered grafting apples onto crabapple stocks a problem, quoting the Levushei Serad (Chiddushei Dinim #106, also quoted by Piskei Teshuvah, Yoreh Deah 295:2) that this graft is prohibited as harkavas ilan. The Mishkenos Yaakov (Shu’t Mishkenos Yaakov, Yoreh Deah #69) discusses some of the varieties of crabapple that were commonly used for grafting apples, and permits grafting an apple scion onto the stock of any of the crabapples available in his area. This conclusion is accepted by several other authorities (Beis Efrayim, quoted by the Mishkenos Yaakov; Shu’t Tzemach Tzedek, Yoreh Deah #221; Aruch Hashulchan, Yoreh Deah 295:15). Thus, again, the difference in scientific species identification has nothing to do with the halachicdefinition.

Conclusion

In all six types of kil’ayim mentioned above, the general criterion is to avoid the appearance of different species being intermingled. Concerning this, Rav Hirsch (Vayikra 19:19) writes, “The Great Lawgiver of the world separates the countless numbers of His creations in all their manifold diversity, and assigns to each one of them a separate purpose and a separate form for its purpose.”

In addition, the laws of kil’ayim help us bear in mind how various species obeyed Hashem’s instructions to remain separate during their creation. This reminds the contemplative Jew that if the plants heeded Hashem’s word during the Creation, how much more we are obligated to obey all His instructions.

Question #1:

“Last time I went to immersesome cutlery, a lady immersing some aluminum bowls asked me to include her with my beracha. When I asked her whether she wanted me to help her recite her own beracha on the mitzvah, she responded softly that she received a psak not to recite a beracha when toiveling aluminum, although she did not know the reason. Why would she not recite the beracha?”

Question #2:

“I have a gift business in which I sell candy dishes with candies, fruits, and nuts already in the glass dishes. Must I toivel these dishes before I fill them?”

Introduction:

In Parshas Matos, the Torah teaches: Only the gold and the silver; the copper, the iron, the tin and the lead: any item that was used in fire needs to be placed in fire to become pure [meaning “kosher”], yet it must also be purified in mikveh water. And that which was not used in fire must pass through water” (Bamidbar 31:22-23). These verses serve as the basis for teaching three different sets of laws:

1. Absorbing Concepts

How to kasher vessels that were used to cook non-kosher foods. An item that was used directly in fire, such as a spit or grate that broiled non-kosher, is kashered only by burning it directly in fire; an item used to cook on top of a fire, such as a pot that cooked non-kosher, may be kashered via a process similar to the way it was used, etc.

2. Tainted Metal

Which items are susceptible to tumah. The Torah here teaches that implements made of metal become tamei (spiritually impure) through contact with a tamei item (such as an animal carcass), and that immersing them in a mikveh restores them to tahor status. An item is susceptible to tumah only when the Torah informs us of this fact – if the Torah never taught that an item can become tamei,it does not, and therefore most items in the world are not susceptible to tumah. (Unfortunately, these laws have limited practical application until Moshiach comes and we again have the parah adumah. At that time, we will be able to live according to the tahor status necessary to observe the mitzvos related to the Beis Hamikdash, terumah and maaser sheini.)

3. Immersed in Holiness

The mitzvah to immerse implements in a mikveh or spring prior to using them for food. The Gemara (Avodah Zarah 75b) notes that this immersion is required even if the vessel has never been used. In other words, this mitzvah is unrelated to the requirement of kashering equipment that was used to prepare non-kosher food and to the laws related to purifying implements that became tamei.

Materials that require tevilah

The Torah teaches that utensils owned by a non-Jew that are made of gold, silver, copper, iron, tin or lead require immersion in a kosher mikveh or spring when they are transferred to Jewish ownership. According to most authorities, this mitzvah is a Torah requirement, although there is a minority opinion that this mitzvah is required only miderabbanan (Rambam, as understood by Pri Chadash). We will assume that the requirement to immerse gold, silver, copper, iron, tin and lead implements is Torah-ordained. (Bear in mind that, although we would not use lead as an ingredient because of valid concerns about lead poisoning, this medical problem was not discovered until the nineteenth century. Therefore, we find much earlier halachic literature discussing immersion of lead or lead-lined utensils.)

There is no requirement to immerse food utensils made of wood, earthenware, ivory, bone, leather, stone or most other materials. We will soon discuss glass and plastic.

Mechiras Chometz and Tevilas Keilim

As we all know, before Pesach one is required to rid one’s house and all one’s possessions of chometz. However, some items, such as toasters, mixers, wooden kneading bowls, and flour bins are difficult, if not impossible, to clean. Shulchan Aruch and Rema (Orach Chayim 442:11) recommend giving wooden kneading bowls and flour bins and the chometz they contain as a gift to a non-Jew before Pesach, with the understanding that the gentile will return them after the holiday. Today, the standard mechiras chometz that we perform includes selling this chometz and these appliances in the sale. However, what do I do if I have metal appliances that may be full of chometz, such as mixers and toasters? If I sell these appliances to a gentile and then purchase the appliance back from him, will I now need to immerse the appliance in a mikveh?

The halachic authorities note that someone selling his or her chometz to a gentile before Pesach should be careful not to sell utensils that require tevilas keilim. Instead, one should rent the appliances to a gentile and sell the chometz they contain (Chachmas Odom; Noda Beyudah, cited in Pischei Teshuvah, Yoreh Deah 120:13). An item rented to a gentile does not require immersion when it is returned to the Jewish owner.

Cleavers versus Graters!

The Gemara (Avodah Zarah 75b) quotes Rav Sheishes as suggesting that anything purchased from a gentile, even a clothing shears, should require immersion. Rav Nachman responded that the mitzvah of tevilas keilim applies only to kelei seudah — literally, implements used for a meal, which includes both utensils used to prepare food, such as pots and knives, and those utilized to eat or drink, such as drinking cups and tableware (Avodah Zarah 75b).

Grates and Grills

One is required to immerse only those items that usually touch the food directly. Therefore, stove grates, blechs, hotplates, knife sharpeners, trivets, can openers and corkscrews do not require tevilah (see Yoreh Deah 120:4), but grills, peelers, funnels, strainers, salt shakers, pepper mills and tongs do require tevilah, since they all touch food.

What about storage vessels?

Is one required to immerse a metal container or glass jar used to store foodstuffs, but that is not suitable for preparing or consuming food?

Rabbi Akiva Eiger (on Yoreh Deah 120:1, quoting Keneses Hagedolah [Beis Yosef 18]) discusses whether storage vessels require tevilah, and concludes that it is unclear whether they should be immersed. Therefore one should immerse them without reciting a beracha, because in case there is no mitzvah to immerse them, reciting a beracha al tevilas keilim before immersing them is reciting a beracha levatalah, a beracha in vain. A better solution is to immerse them at the same time that one immerses an item that definitely requires a beracha.

Kelei Sechorah — “Merchandise”

The halachic authorities note that a storekeeper does not toivel vessels he is planning to sell, since for him they are not kelei seudah, but items he intends to sell. Later authorities therefore coined a term “kelei sechorah,” utensils used as merchandise, ruling that these items do not require immersion until they are purchased by the person intending to use them (based on Taz, Yoreh Deah 120:10). Furthermore, several halachic authorities contend that the storekeeper cannot immerse the vessels prior to sale, since there is as yet no requirement to immerse them (Shu’t Minchas Yitzchak 8:70). This is based on a statement of the Rema that implies that a tevilah performed before one is obligated to immerse a vessel, such as while it is still owned by the gentile, does not fulfill the mitzvah and must be repeated after it becomes the property of a Jew (Rema Yoreh Deah 120:9).

Based on this discussion, we can now address one of our above-mentioned questions:

“I have a gift business in which I sell candy dishes with candies, fruits, and nuts already in the glass dishes. Must I toivel these dishes before I fill them?”

This question is a modification of a situation in which I was involved. I once received a glass candy dish from someone, with a note from the business stating that the dish has already been toiveled. I called the proprietor of the business to inform him that, in my opinion, not only is he not required to toivel the dish, but I suspect that it does not help. My reasoning is that, although the proprietor fills his dishes with nuts and candies, from his perspective this is still merchandise that he is selling. The dish therefore qualifies as kelei sechorah which one need not immerse, and, therefore, immersing them does not fulfill the mitzvah. As a result, not only is the proprietor not obligated to immerse the dishes, but doing so fulfills no mitzvah, and it is a beracha levatalah for him to recite a beracha on this immersion. Including a note that the dish was toiveled is detrimental, since the recipient will assume that he has no requirement to toivel this dish, whereas, in fact, the end-user is required to immerse it. For these reasons, I felt it incumbent on myself to bring this to the attention of the owner of the business.

The proprietor was very appreciative. He told me that, in truth, it was a big hassle for him to toivel the dishes, but he had been assuming that halacha required him to do so before he could fill the dishes.

Some Immersing Details

When immersing the utensil, one should not hold it very tightly in one’s hand, since this will cause the part of the utensil he is holding to not be immersed properly. Instead, one should either hold the utensil somewhat loosely, or alternatively, one should dip one’s hand into the mikveh water before holding the utensil that will be immersed (Rema, Yoreh Deah 120:2; see Taz and Shach).

Prior to immersing a utensil, one must remove all rust and dirt from the utensil. If one immersed the utensil and it had rust or dirt that most people would not want on the appliance, one must clean it, and then re-immerse it (Yoreh Deah 120:13).

When one is immersing an item that definitely requires tevilah, immediately prior to dipping it, one should recite the beracha, Asher kideshanu bemitzvosav vetzivanu al tevilas keili. If one immerses more than one vessel he should conclude instead al tevilas keilim (Yoreh Deah 120:3). Although some authorities mention alternative texts to the beracha, I have quoted the commonly used text, which follows the majority opinion.

If it is uncertain whether the item requires tevilah, one should not recite a beracha. It is preferable, if possible, to immerse it at the same time that one immerses a different utensil that definitely requires tevilah, so that both items are included in the beracha.

May a child toivel keilim?

If a child tells you that he immersed a vessel in a kosher mikveh, may you rely that this indeed happened?

The halacha is that if an adult supervised the child immerse the vessel correctly, one may use the utensil, but one may not rely on the child attesting that he or she immersed the utensil properly (Yoreh Deah 120:14; see also Gr”a ad locum and Pri Megadim, Orach Chayim, Mishbetzos Zahav 451:6). Apparently, this is not a well-known halacha, since one often finds children being used as agents to immerse utensils for their parents.

People eating from glass dishes…

The Gemara teaches that food utensils made of glass must be immersed prior to use, since glassware is similar to metalware in that when it becomes broken it can be melted and repaired, what we usually call recyclable.One recites a beracha prior to immersing glassware, just as one recites a beracha prior to immersing metalware.

Of course, this leads us to a question about plasticware, since many forms of plastic are recyclable in ways very similar to metal and glass. Does repairable plasticware require tevilah just as glassware does? Most people assume that plasticware is not included in the mitzvah of tevilas keilim, but why?

This takes us to an earlier discussion between 19^th-century poskim concerning a type of boneware, which, when broken or cracked, could be repaired by melting and melding it. (I personally have no experience with this material, but I imagine that one could probably melt and repair bone, just as one can repair horn by melting and melding. There is much halachic discussion about the repair of a damaged shofar by melting and melding the crack.) Rav Avraham Shaag, the rebbe of Rav Yosef Chayim Sonnenfeld (later the Rav of the old Yishuv of Yerushalayim and Eretz Yisrael), concluded that just as one is required to immerse glassware because it is repairable, one is required to immerse boneware (Shu’t Ohel Avraham #24, quoted by Darkei Teshuvah). This position was disputed by Rav David Zvi Hoffman, the preeminent posek of Germany in his day, who contended that since the immersion of glassware is required only miderabbanan, one need immerse only those items that Chazal specifically required, but a newly developed material, albeit similar to glassware, would not require immersion (Shu’t Melamed Leho’il, Yoreh Deah #49).

The late authorities debate whether plastic items require immersion prior to use. Indeed, some authorities (Shu’t Minchas Yitzchak 3:76) require the immersion of reusable plastic plates and the like, because they follow the logic of Rav Avraham Shaag — although without a beracha, since perhaps Rav Dovid Hoffman is halachically correct. Nevertheless, most authorities conclude that one is not required to immerse plasticware (Shu’t Yabia Omer 4: Yoreh Deah: 8; Tevilas Keilim page 226).

Other Metals

When teaching that metal implements become tamei and that one must immerse food utensils before use, the Torah specifies the six metals that were available in ancient times: gold, silver, copper, iron, tin and lead. (Bronze and brass are both alloys whose main component is copper; in bronze, the most significant minority element is tin, and in brass it is zinc.) However, over the last two hundred years, mankind developed the means to extract and process several other metals, including platinum, chromium, aluminum, and titanium. Do these “new” metals have the same halachic status as the six mentioned in the Torah? Are platinum rings, aluminum urns and titanium airplanes susceptible to tumah?  Do chrome pots and aluminum trays require tevilas keilim?

The Tiferes Yisrael, in his extensive introduction to the Order of Taharos, rules that the newly discovered metals have the same halachic status as the six mentioned explicitly by the Torah, and they are all capable of becoming tamei (Yevakeish Daas #44). It follows from his line of reasoning that one is required min haTorah to immerse food vessels made of the new types of metal, and indeed this is how many authorities rule (Tevilas Keilim page 225). Many authorities contend that, although one is required to immerse aluminum pots, one is not required to immerse aluminum items that are disposable. Since they are meant to be disposed after use, they are not considered “keilim” that require immersion.

On the other hand, other poskim dispute the Tiferes Yisrael’s conclusion that all types of metal become tamei, contending that since the Torah mentions six specific metals (and the Torah could certainly have used a generic term for all metal items that would have been much briefer), choosing a lengthy way of listing six types of metal demonstrates that these are the only types of metal that become tamei, and that any newly developed metals are not susceptible to tumah (Shu’t Igros Moshe, Yoreh Deah 2:164; letter from Rav Yaakov Kamenetsky published at end of the sefer Tevilas Keilim).

According to the latter approach, one can argue that chrome pots and aluminum implements do not require tevilas keilim. The prevalent accepted practice is to assume that they do require tevilas keilim, although some authorities consider this a sufficient enough doubt to omit the beracha prior to immersing these items.

Conclusion

According to Rav Hirsch, metal vessels, which require mankind’s mining, extracting and processing, represent man’s mastery over the earth and its materials. Whereas vessels made of earthenware or wood only involve man shaping the world’s materials to fit his needs, the manufacture of metal demonstrates man’s creative abilities to utilize natural mineral resources to fashion matter into a usable form. Consuming food, on the other hand, serves man’s most basic physical nature. Use of metal food vessels, then, represents the intellectual aspect of man serving his physical self, which, in a sense, is the opposite of why we were created, which is to use our physical self to assist our intellect to do Hashem’s will. Specifically in this instance, the Torah requires that the items hereby produced be immersed in a mikveh before we use them, in order to endow them with increased kedusha before they are put to food use. This demonstrates that although one may use one’s intellect for physical purposes, when doing so one must first sanctify the item, to focus on the spiritual.

Question #1: Pie r Squared

Yanki is supposed to be watching his weight and therefore needs to figure out how many calories are in the pie he beholds. To figure out how big the pie is, he measures the diameter of the pie, and divides in it half to get the length of its radius. He then multiplies the length of the radius by itself to get “r squared,” and multiplies the result by three so that he knows the area of the pie’s surface. Is there anything wrong with his calculation?

Question #2: Puzzled by the Pasuk

“How can the pesukim tell us that the relationship between the circumference of a circle and its diameter is three to one, when simply taking a string and measuring around a circle demonstrates that the circumference is noticeably longer than three times the diameter?”

Question #3: Performing Mitzvos Accurately

“How accurate a calculation must I make when determining the size of an item to be used for a mitzvah?”

Introduction

In numerous places, both Tanach and Chazal approximate certain mathematical values, such as evaluating the ratio of the circumference of a circle to its diameter as three to one. The problem is that we can demonstrate mathematically that the ratio is greater than three and is almost 3 1/7. This leads to the following questions:

(1) Why would Chazal calculate using inaccurate approximations?

(2) When making halachic calculations, may we rely on these estimates, or do we need to be mathematically more accurate?

(3) A corollary question is: When providing an estimate, one must allow for a margin of error. Does halachah require a margin of error, and, if so, how much?

The Slide Rule versus the Calculator

Let me begin our discussion with a modern analogy, if something I remember can still be considered “modern.” When I first studied sophisticated mathematical estimates, I learned to use a slide rule, which today is as valuable to an engineer as his abacus. Relative to the calculator, a slide rule does not provide accurate measurements, and someone using a slide rule must allow for a fairly significant margin of error.

Today, complex computations are made with calculators, which provide far more accurate results that can be rounded off, as necessary, to the nearest tenth, millionth, quadrillionth or smaller. Of course, using a calculator still requires one to round upward or downward, but because it is much more precise, the margin of error is greatly reduced.

How Irrational Are You?

Numerous halachic questions require mathematical calculations that involve what we call “irrational numbers.” An irrational number means one that cannot be expressed in fractional notation. Another way of explaining an irrational number is that its value can never be calculated totally accurately, but can only be estimated. The two most common examples of irrational numbers that show up in Chazal are:

Pi

(1) The ratio of the circumference of a circle to its diameter, which we are used to calling by the Greek letter ∏ (pronounced like the word “pie,” and spelled in English “pi”). Since the 19^th century, the letter pi has been used to represent this number, because the Greek word for periphery is peripherion, which begins with the letter ∏. Hundreds of years earlier, the Rambam (Commentary to the Mishnah, Eruvin 1:5) noted that the ratio of the circumference of a circle to its diameter is an irrational number that can only be approximated, and that the scientists of his era used an estimate of 3 and 1/7, which is actually slightly greater than the value of ∏. The Rambam explains that since there is no accurate ratio, Chazal used a round number, three, for this calculation.

The Diagonal of a Square

(2) The length of a diagonal of a square, which is equal to the side of the square multiplied by the square root of two (√2). Chazal calculated the length of a diagonal of a square to be 1 and 2/5 times its side, which is slightly smaller than the value of the √2. (Another way of expressing this idea is that the ratio between the diagonal and the side is 7:5.) The fact that Chazal’s figuring is somewhat smaller than the mathematical reality is already proved by Tosafos (to Sukkah 8a s.v. kol).

Since both pi and the square root of two are irrational numbers, they can only be estimated but can never be calculated with absolute accuracy.

Based on the above-quoted statement of the Rambam, we can already address one of our earlier questions: “Why would Chazal have used inaccurate evaluations for calculation?” The answer is that any computation of the correlation of the circumference of a circle to its diameter will be an estimate. The only question is how accurate must this estimate be for the purpose at hand.

Chazal or Tanach?

Although the Rambam attributes the rounding of pi to Chazal, in actuality, there are sources in Tanach that calculate the ratio of the circumference of a circle to its diameter as three-to-one. Both in Melachim (I 7:23) and again in Divrei Hayamim (II 4:2), Tanach teaches that the Yam shel Shelomoh, the large, round pool or mikveh that was built in the first Beis Hamikdash, was thirty amos in circumference and ten amos in diameter, which provides a ratio of circumference to diameter of three-to-one. Thus, we can ask a question of the Rambam: Why does he attribute this ratio to Chazal, rather than the source for Chazal’s calculation, the pesukim?

The commentaries there, however, already ask how the verse can make a calculation that we know is not accurate. The Ralbag suggests two options: either that the numbers used are intended to be a very broad estimate, or, alternatively, that the diameter is measured from the external dimensions of the mikveh, whereas the circumference is measured from its inside, which makes the estimate closer to mathematical reality. According to the second approach, we have no Biblical source that uses an estimate of three-to-one as a substitute for pi.

This will explain why the Rambam attributed the estimation of pi as three to Chazal, rather than to the Tanach. The Rambam was fully aware that one could interpret the verses according to the second approach of the Ralbag, in which case, there is no proof from the verse. He, therefore, attributed this estimate to Chazal.

Gemara Eruvin

However, the Ralbag’s approach seems to conflict with a passage of Gemara. The Mishnah in Eruvin states that if the circumference of a pole is three tefachim, its diameter is one tefach, which means that the Mishnah assumes a ratio of three-to-one.

The Gemara questions how the Mishnah knows that the ratio is three-to-one, and then draws proof from the above-quoted verse that the Yam shel Shelomoh was thirty amos around and ten amos across. The Gemara then debates whether the calculations of the Yam shel Shelomoh indeed result in a ratio of three-to-one, because one must also include the thickness of the poolitself, which offsets the computation. The Gemara eventually concludes that the verse was calculating from the inside of the pool, not its outside, and therefore the thickness of the pool’s containing wall is not included in the calculation (Eruvin 14a).

However, this Gemara’s discussion leaves the mathematician dissatisfied, a question already noted by Tosafos. If the internal diameter of the Yam shel Shelomoh was ten amos, its circumference must have been greater than thirty amos, and if its circumference was thirty amos, then its internal diameter must have been less than ten amos.

A Different Question

The Rosh, in his responsa, is bothered by a different question, based on Talmudic logic rather than on mathematical calculation. He finds the Gemara’s question — requesting proof for the ratio between a circle’s circumference and its diameter — to be odd. The ratio between a circle’s circumference and its diameter is a value that one should calculate. By its nature, this is not a question that requires a Biblical proof or source.

In the literature that we have received from the Rosh, he asks this question in two different places. In his responsa (Shu”t Harosh 2:19), we find a letter that he wrote to the Rashba, in which he asked a series of questions that the Rosh notes bother him tremendously and to whom he has no one else to turn for an answer. One of the questions the Rosh asks is: “Why does the Gemara ask for a Biblical source for a mathematical calculation?”

It is curious to note that a later commentary mentions that, in all the considerable literature that we have received from the Rashba, we have no recorded answer of the Rashba to this question of the Rosh (Cheishek Shelomoh to Eruvin 14a).

Another Rosh

As I mentioned above, there is another place where the Rosh asks why the Gemara wanted a Biblical source for a mathematical calculation, but in this second place the Rosh provides an answer to the question. In his Tosafos Harosh commentary on Eruvin, which was published for the first time fairly recently, the Rosh provides the following answer: Since the calculation of three-to-one is not accurate, the Gemara wanted a biblical source as proof that we are permitted to rely on this estimate.

(It is curious to note that the Cheishek Shelomoh whom I quoted above provided the same answer to this question as did the Rosh in his Tosafos. The Cheishek Shelomoh never saw the Tosafos Harosh, which had not yet been printed in his day.)

Curiousity about the Tosafos Harosh

There is an interesting historical point that can presumably be derived from this statement of the Rosh. As I mentioned, in the Tosafos Harosh, the Rosh does answer the question that he raised, and accredits this answer to himself. This should be able to prove which work the Rosh had written earlier, and also whether he ever received an answer to his question from the Rashba. This analysis is based on the following question: Why did the Rosh cite an answer in his Tosafos¸but not in his responsum, which was addressed as a question to the Rashba. There are three obvious possibilities:

(1) Although the Rosh wrote this answer in his Tosafos, he was dissatisfied with it, and therefore wrote a question to the Rashba. I would reject this possibility because, if it is true, then, in his correspondence to the Rashba, the Rosh would have mentioned this answer and his reason for rejecting it.

(2) The Rosh indeed received an answer, either this one or a different answer, from the Rashba. I reject this approach also, because, were it true, the Rosh would have quoted the Rashba’s answer in his Tosafos and, if need be, discussed it.

(3) Therefore, I conclude that the Rosh, indeed, never received an answer to the question he asked of the Rashba and subsequently reached his own conclusion as to how to answer the question, which he then recorded in the Tosafos Harosh. This would lead us to conclude that the Tosafos Harosh were written later in his life than his responsa, or, at least, than this responsum.

Mathematical Accuracy

At this point, we can address one of earlier questions. “When making halachic calculations, may we rely on these estimates, or do we need to be mathematically more accurate?” We might be able to prove this point by noting something in the Mishnah in Eruvin. The Mishnah there ruled that, under certain circumstances, an area that is fully enclosed on three of its sides and has a beam, a tefach wide, above the fourth side, is considered halachically fully enclosed, and one may carry inside it. The Mishnah then proceeds to explain that if the beam is round and has a circumference of three tefachim, one may carry inside the area because, based on the calculation that the relationship of its circumference to its diameter is three-to-one, the beam is considered to be a tefach wide. However, as the Rambam notes, the beam is actually less than a tefach in diameter, and therefore, one should not be permitted to carry in this area!

The Aruch Hashulchan (Orach Chayim 363:22; Yoreh Deah 30:13) notes this problem and concludes that one may carry in this area. He contends that this is exactly what the Gemara was asking when it requested Scriptural proof for a mathematical calculation. “Upon what halachic basis may we be lenient in using this estimate of three-to-one, when this will permit carrying in an area in which the beam is less than a tefach wide? The answer is that this is a halachah that we derive from the verse.”

To clarify this concept, the Chazon Ish notes that the purpose of mitzvos is to draw us nearer to Hashem, to accept His reign, and to be meticulously careful in observing His laws. However, none of this is conflicted when the Torah teaches that we may use certain calculations, even if they are not completely mathematically accurate. In this instance, relying on these estimates is exactly what the Torah requires (Chazon Ish, Orach Chayim 138:4). As expressed by a different author, the Gemara (Eruvin 4a; Sukkah 5b) teaches that the measurements, the shiurim, required to fulfill mitzvos are all halachah leMoshe miSinai, laws that Moshe Rabbeinu received as a mesorah in Har Sinai. Similarly, these estimates of irrational numbers mentioned above are all halachah leMoshe miSinai that one may rely upon to fulfill mitzvos, whether or not they are mathematically accurate. The same Torah takes these calculations into consideration when instructing us which dimensions are required in order to fulfill these specific mitzvos (Shu”t Tashbeitz 1:165).

In the context of a different halachah in the laws of Eruvin, the Mishnah Berurah makes a similar statement, contending that we can rely on Chazal’s estimates, even when the result is lenient. However, the Mishnah Berurah there vacillates a bit in his conclusion, ruling that one can certainly rely on this when the issue is a rabbinic concern (Shaar Hatziyun 372:18). In a responsum, Rav Moshe Feinstein questions why the Mishnah Berurah limits relying on this approach, and Rav Moshe rules unequivocally that the rule permitting one to rely on these estimates holds true even germane to de’oraysa laws and even leniently (Shu”t Igros Moshe, Yoreh Deah Volume3 #120:5).

How Straight Are My Tefillin?

Personally, I find the context of Rav Moshe’s teshuvah very interesting. There is a halachah leMoshe miSinai that requires that the boxes of the tefillin, the batim, must be perfectly square. In a responsum dated 21 Adar II, 5736, Rav Moshe was asked whether there is a halachic preference to use scientific measuring equipment to determine that one’s tefillin are perfectly square. Rav Moshe rules that there is neither a reason nor a hiddur to measure the tefillin squareness this accurately. Since Chazal have used the calculation of 1.4 or a ratio of 7:5, which we know is an estimate, to determine the correct diagonal of a square, there is no requirement to make one’s tefillin squarer than this, and it is perfectly fine simply to measure the length of each of the sides of one’s tefillin and its two diagonals to ascertain that the ratio between the diagonal and the side is 7:5.

In the above-cited responsum, Rav Moshe notes that he had heard that the Brisker Rav, Rav Yitzchak Ze’ev Soloveitchik, had ruled that it was preferable to check one’s tefillin in the most scientific method available. Rav Moshe writes that he finds this suggestion very strange and disputes its being halachically correct (Shu”t Igros Moshe, Yoreh Deah Volume3 #120:5).

Thus, according to these authorities, we have answered our previous question regarding the halachic significance of estimated values: Indeed, the purpose of Chazal‘s making these estimates was that observing halachah does not require that these calculations be mathematically precise, provided they meet the criteria that the halachah established.

An Alternate Approach

Although the majority of late authorities conclude that the calculations of Chazal are indeed part of the halachos of shiurim, this is not a universally held position. The Tashbeitz, a rishon, wrote a lengthy responsum on the topic, in which he presents two ways to explain why Chazal used estimates that are not precisely accurate. His first approach reaches the same conclusion as we have already found in the later poskim, that these measurements are included within the halachos of shiurim that are part of the halachah leMoshe miSinai.

The second approach of the Tashbeitz, however, differs with the above-mentioned halachic conclusion. In his second approach, he contends that all the above estimates were meant for pedagogic, but not halachic reasons. The rounding of pi to three and the diagonal of a square to 1.4 were provided to make the material easily comprehensible to all students, since every individual is required to know the entire Torah. Thus, when Chazal used these estimates in calculating the laws, their intent was to enable the average student to comprehend the halachic material, not to provide the most accurate interpretation. When an actual halachic calculation is made, it must be totally accurate, and any halachic authority involved would realize that he must use a highly accurate mathematical computation and then round either upward or downward as necessary for the specific application. (A similar position is held by Chiddushim Uviurim, Ohalos 5:6.)

Conclusion

Certainly, the majority of late halachic opinions conclude that the estimates of Chazal are meant to be halachically definitive, and not simply pedagogic in nature. However, I leave it to the individual reader to ask his or her posek what to do when a practical question presents itself.

The midrash at the beginning of this week’s parsha mentions that the details of all mitzvos were taught at Sinai, making this topic extremely timely…

Question #1: Choosing your Mitzvos

“I don’t have enough money for all the mitzvah objects that I need. Which should I purchase?”

Question #2: Extra Mezuzos

“I have extra mezuzos. May I use them for tefillin?”

Question #3: When Do We Recite a brocha?

“Why don’t we recite a brocha when we put tzitzis onto a garment, yet we recite a brocha when we affix a mezuzah to a door?”

Introduction

The first two of our opening questions deal with a very interesting issue: Are there hierarchies among our mitzvos? In other words, are some mitzvos more important than others?

We do not usually attempt to judge which mitzvah is more important, since it is our obligation to observe all the mitzvos to the best of our ability. Nevertheless, there are occasional circumstances when we must decide which mitzvah is more “valuable.” One example when this could happen is when we must choose between observing one mitzvah and another. The Gemara (Rosh Hashanah 34b) discusses a situation in which one has to choose whether to spend Rosh Hashanah in a place where there is someone to blow shofar, but no Rosh Hashanah davening, or in another place where there is Rosh Hashanah davening, but no shofar. The Gemara concludes that it is more important to spend Rosh Hashanah in a place where there might be an opportunity to fulfill the mitzvah of shofar, than to go somewhere else where there will definitely be davening but no shofar blowing. This is because safek d’oraysa, a possibility of fulfilling a mitzvah min haTorah,carries more weight than definitively fulfilling that which is required only miderabbanan.

Yerushalmi

A more revealing and detailed discussion is in the Talmud Yerushalmi, at the very end of Mesechta Megillah, which quotes a dispute between Shmuel and Rav Huna concerning someone who has only sufficient money to purchase either tefillin or mezuzah, but not both. The question debated in the passage of the Yerushalmi is: Which mitzvah is it more important to fulfill? The explanations provided in this passage of the Yerushalmi provide insight into other mitzvos, should these rules need to be applied. For example, should someone have to choose between purchasing the four species for Sukkos or materials for a sukkah, which takes precedence? (For simplicity’s sake throughout the rest of this article, I will refer to the purchasing of the four species for Sukkos as simply the mitzvah of “lulav.”) Or, should one have to choose between purchasing a lulav or purchasing tefillin, which takes precedence? This passage of Yerushalmi provides foundation for subsequent halachic discussion on these issues.

Let us quote the passage of the Yerushalmi:

Tefillin and mezuzah, which comes first? Shmuel said, “Mezuzah comes first.” Rav Huna said, “Tefillin comes first.” What is Shmuel’s reason? Because mezuzah applies on Shabbos and Yom Tov. What is Rav Huna’s reason? Because tefillin applies to people traveling on the seas and in deserts. A beraisa (teaching of the era of the Mishnah, but not included in the Mishnah) supports Shmuel, which says that if tefillin have worn out, one may use its parshiyos (written parchments) for mezuzah, but one may not use a mezuzah for tefillin, since we have a general rule that one increases but does not decrease sanctity.

To explain the Yerushalmi’s conclusion: The mitzvah of tefillin requires use of four sections of the Torah, two in parshas Bo, and two others, the first two of the three parshiyos of kerias shma, which are from parshas Va’eschanan and parshas Eikev. A mezuzah includes only these last two sections of the Torah. May one take the pieces of parchment that were used as a mezuzah and use them for tefillin, or vice versa — if they were used for tefillin can they be used for a mezuzah?

Understanding Shmuel

Shmuel contends that since mezuzah applies every day of the year, it is a greater and holier mitzvah than tefillin. The Gemara quotes two ramifications of this ruling:

(1) Should one be able to fulfill only one of these two mitzvos, mezuzah is preferred.

(2) Parshiyos once used for tefillin may be used for a mezuzah, but a mezuzah may not be used for parshiyos in tefillin. Since mezuzah is a holier mitzvah, using a mezuzah for tefillin decreases its sanctity, which is not permitted. This is because of a general halachic rule, maalin bekodesh velo moridim:something may be elevated to a use that is of greater sanctity, but it may not be reduced to a lower level of sanctity. For example, a kohein gadol can never return to being a kohein hedyot, a regular kohein. Since the beraisa quoted by the Yerushalmi states that one may not use mezuzah parshiyos for tefillin, the conclusion is, like Shmuel, that mezuzah is more important.

There is a question on Shmuel’s explanation. In what way does mezuzah apply on Shabbos and Yom Tov, when one is not permitted to put a mezuzah on a door on either of these holidays, because of the melacha involved? The answer is that, if someone is required to affix a mezuzah but did not, he is not permitted to spend Shabbos in that house unless he has nowhere else to live (see Pri Megadim, Orach Chaim, Eishel Avraham 38:15; Aruch Hashulchan, Yoreh Deah 285:5). In other words, although one may not install a mezuzah on Shabbos or Yom Tov, the mitzvah still applies on those days.

Understanding Rav Huna

Rav Huna explains that on days that one is obligated to wear tefillin, there are no exemptions from that responsibility. On the other hand, someone who has no residence is not obligated in mezuzah. In theory, one can exempt oneself from the mitzvah of mezuzah by avoiding living in a residence. Therefore, tefillin is a greater mitzvah than mezuzah.

This has two ramifications:

(1) Should one be able to fulfill only one of these two mitzvos, tefillin is preferred.

(2) A mezuzah may be used for parshiyos in a pair of tefillin, but parshiyos used for tefillin may not be used for mezuzah. Since tefillin is a holier mitzvah, using parshiyos of tefillin for a mezuzah decreases their sanctity, which is not permitted.

How do we rule?

The Rosh (Hilchos Tefillin, Chapter 30) rules that the mitzvah of tefillin is more important, and this approach is followed by the Tur, the Shulchan Aruch (Orach Chayim 38:12), the Rema (Yoreh Deah 285:1) and the later authorities. The Rosh explains that tefillin is more important because a mitzvah de’gufei adif, literally “a mitzvah of your body is more important.” What does this mean?

One early acharon, the Beis Hillel (Yoreh Deah 285), understood the Rosh to mean that the mitzvah of tefillin is more important because one puts tefillin on his body, as opposed to mezuzah, which is on one’s house, not body. Based on his reason, the Beis Hillel concludes that tefillin is more important than sukkah or lulav, since neither of these mitzvos is performed on one’s body to the extent that tefillin is. Once the Beis Hillel is discussing which mitzvos are “more important,” he discusses whether tefillin is more important than tzitzis or vice versa, concluding that tefillin are more important, since the name of Hashem is in the tefillin.

However, most authorities understand that the Rosh means something else. They explain that the mitzvah of tefillin is inherently obligatory, whereas the mitzvah of mezuzah is circumstantial. Every weekday there is an obligation for every adult Jewish male to don tefillin. The mitzvah of mezuzah is not inherently obligatory, but is dependent on one’s living arrangements, and can be avoided completely (Gra; Rabbi Akiva Eiger, in his notes to Shulchan Aruch and Responsum 1:9; Aruch Hashulchan, Yoreh Deah 285:5). Furthermore, according to most authorities, mezuzah is obligatory min haTorah only if one owns the house in which he lives.

A big difference between these two approaches is germane to the mitzvos of lulav and sukkah. According to the Beis Hillel, these mitzvos carry less weight than tefillin. However, according to those who disagree with him, both of these mitzvos are inherently obligatory, just as tefillin. This would mean that, regarding the Rosh’s criterion, all three of these mitzvos should be treated on an equal footing, and we would need to find other criteria to decide which of them is more important.

Tefillin or Sukkah?

Rabbi Akiva Eiger notes that the above-discussed passage of Yerushalmi provides an answer to this question. There it stated that a mitzvah that occurs more frequently should be prioritized over one that occurs less frequently. Tefillin is far more frequently observed than either sukkah or lulav, and, therefore, should be treated with more priority than they are.

However, notes Rabbi Akiva Eiger, this question is usually moot for the following reason: When one has a mitzvah that he is obligated to observe immediately, he does not wait to fulfill it. Therefore, any time other than erev Sukkos, one who needs to choose between these mitzvos should use the funds to acquire tefillin, since he has that responsibility immediately, and the mitzvos of Sukkos will wait. If the situation occurs during chol hamoed Sukkos, the priority will be: sukkah, tefillin, lulav. This is because the mitzvah of sukkah is, at the moment, definitely min haTorah, whereas even those who wear tefillin on chol hamoed accept that it is disputed whether there is a mitzvah to wear them on chol hamoed. Therefore, sukkah, which is definitely a requirement min haTorah on all seven days of Sukkos, takes precedence over tefillin. Since the mitzvah of taking lulav is min haTorah only on the first day of Sukkos, but afterwards is required only miderabbanan (unless one is in or near the Beis Hamikdash grounds), tefillin will have precedence over lulav for those who wear tefillin on chol hamoed, which is the assumption that Rabbi Akiva Eiger makes.

Tefillin versus tzitzis

Rabbi Akiva Eiger agrees that tefillin is more important than tzitzis, but for a different reason than that provided by the Beis Hillel. Tzitzis is like mezuzah – there is only an obligation if he has a four-cornered garment, but it is not an automatic requirement. Although one is obligated to place tzitzis on any four-cornered garment that one owns and wears, one can avoid wearing four-cornered garments more easily than one can avoid living in a house that one owns. On the other hand, a man is required to wear tefillin every weekday.

Difficulty with the Rosh

Notwithstanding that all later authorities conclude that tefillin is considered a more “important” mitzvah than mezuzah, a difficulty is presented by the Rosh’s conclusion. Why would he rule according to Rav Huna, when the Yerushalmi’s conclusion is, like Shmuel, that mezuzah is a more important mitzvah?

The answer is that the Talmud Bavli (Menachos 32a) states the following: “A sefer Torah that wore out, or tefillin that wore out, cannot be used for a mezuzah, because one is not permitted to reduce something from a greater sanctity to a lower one.” Thus, we see that the Bavli ruled according to Rav Huna, that tefillin is a greater mitzvah than mezuzah, and the halacha follows the Bavli over the Yerushalmi (Beis Yosef, end of Orach Chayim, Chapter 38).

Practically speaking

The Magen Avraham (38:15), one of the major halachic authorities, notes that, although the mitzvah of tefillin is more important than mezuzah, in practice it might be better for someone to purchase mezuzos. Someone might be able to coordinate his schedule such that he can borrow tefillin from other people when he needs them for davening every day, something impractical to do with mezuzos. Thus, if he can thereby observe both mitzvos, he should purchase the mezuzos to allow this. This ruling is followed by the later authorities (Shulchan Aruch Harav; Mishnah Berurah; Aruch Hashulchan).

Nevertheless, the rule has not changed: Someone who will be unable to observe the mitzvah of tefillin should purchase tefillin first and wait until he has more resources before he purchases mezuzos (Shulchan Aruch Harav; Mishnah Berurah; Aruch Hashulchan).

Choosing your mitzvos

At this point, we can now address our opening question: “I don’t have enough money for all the mitzvah objects that I need. Which should I purchase?”

The halachic conclusion is:

He should first see which mitzvos he can fulfill without purchasing them. For example, he might be able to borrow tefillin, and he also might be able to use someone else’s sukkah. If he lives near someone else who is observant, he should be able to fulfill the mitzvah of lulav with someone else’s lulav. In earlier generations, it was common for an entire community to purchase only one set of four minim, and everyone used that set to fulfill the mitzvah. Mezuzah is more difficult to observe with borrowed items, and, therefore, he might need to purchase mezuzos ahead of tefillin, lulav, or sukkah, notwithstanding that they are obligatory mitzvos to a greater extent than mezuzah is.

Furthermore, which mitzvah he will need to observe first might be a factor, as we saw from Rabbi Akiva Eiger’s discussion about someone who needs to purchase tefillin, sukkah and lulav.

When Do We Recite a Brocha?

At this point, we can discuss the third of our opening questions: “Why don’t we recite a brocha when we put tzitzis onto a garment, yet we recite a brocha when we place a mezuzah on a door?”

This question is raised by the Magen Avraham, in his commentary on the following words of the Shulchan Aruch (Orach Chayim 19:1): “Until one dons the garment, one is exempt from putting tzitzis on it. For this reason, one does not recite a brocha when one places the tzitzis on the garment, since the mitzvah is only when you wear it.”

The Magen Avraham (19:1) asks why we do not recite a brocha when putting tzitzis onto a garment, yet we recite a brocha when we affix a mezuzah to a door? The Magen Avraham answers that the reason is practical. Usually, one moves into the house first, before he installs the mezuzah, and, since he already lives in the house, he is responsible to have a mezuzah on the door. Thus, placing the mezuzah on the door is the fulfillment of the mitzvah and warrants a brocha. On the other hand, one does not usually place tzitzis on a garment while wearing it, but before he puts it on, when there is no obligation yet to fulfill a mitzvah.

Based on his analysis, the Magen Avraham rules that should any of the tzitzis tear off a garment while someone is wearing it, and he attaches replacement tzitzis while he is still wearing it, he should recite a brocha prior to attaching the replacement. The brocha he would recite in this instance is Asher kideshanu bemitzvosav vetzivanu la’asos tzitzis, which translates as a brocha “to make tzitzis,” a text that we do not have recorded by any earlier authority.

Notwithstanding his conclusion, the Magen Avraham rules that this is not the preferable way to act, but, rather, he should remove the tzitzis once they become invalid and attach replacement tzitzis without a brocha. On the other hand, the Magen Avraham contends that if a mezuzah falls off or becomes invalid, the occupant is not required to relocate until he can replace the mezuzah. The difference between the two cases is how much tircha the person is required to undergo – one is required to remove a pair of tzitzis, which is a simple act, but not required to relocate himself and his family until he has a chance to replace or reaffix the mezuzah.

The Magen Avraham then suggests that if someone affixed a mezuzah before he moved into a house, he should not recite the brocha when he affixes the mezuzah, but when he moves in he should recite the brocha, Asher kideshanu bemitzvosav vetzivanu ladur babayis sheyeish bo mezuzah, “to live in a house that has a mezuzah,” again, a new text of a brocha not recorded by any earlier authority.

The Birkei Yosef (Orach Chayim 19:2) disagrees with the Magen Avraham, contending that we should not create texts of brochos that we do not find in early sources. In regard to the Magen Avraham’s question, why do we recite a brocha upon affixing a mezuzah but not upon placing tzitzis, the Birkei Yosef provides a different answer: Chazal required a brocha on the last act that you do to fulfill a mitzvah. In the case of tzitzis, it is when you put on the garment. In the case of mezuzah, it is when you affix it. However, if there is a mezuzah on the door already, one does not recite a brocha upon moving into a house, since one did not perform any act to fulfill the mitzvah.

Conclusion

A famous quotation from a non-Jewish source is: “Is G-d more concerned about what comes into our mouth or what comes out?” This question assumes that some of Hashem’s mitzvos are more “important” for us to observe than others. The Torah’s answer is that it is not for us to decide which of the mitzvos is more important. One grows in one’s relationship with Hashem through each opportunity to perform a mitzvah.

Parshas Kedoshim contains one of the two places in the Torah where the mitzvos of kil’ayim are taught.

Question #1: Kil’ei beheimah

May one attempt to crossbreed a mule with a stallion?

Question #2: Kil’ei zera’im

May I plant the vegetables in my garden close together?

Question #3: Kil’ei hakerem

Is there any way that I can plant vegetables near my vineyard?

Question #4: Harkavas ilan

Must I be careful before I purchase a fruit tree?

Many people assume that the halachic definition of the mitzvah of kil’ayim is the crossbreeding of different species of plants or animals, but, as we will soon see, not all of the laws of kil’ayim have to do with what a farmer or a scientist would call crossbreeding or hybridization.

My desktop dictionary defines hybrid as “the offspring produced by breeding plants or animals of different varieties, species, or races.” Thousands of years ago, mankind crossbred horses and donkeys to create mules and hinnies. This hybrid, called a pered (female pirdah) is already mentioned many times in Tanach. As a pack animal, the mule — produced from a male donkey, called a “jack” and a mare (female horse) — has many advantages over either of its parents. It is usually as strong as a horse, sturdy, sure-footed, and, notwithstanding its reputation for being “stubborn as a mule,” is more reliable for hauling than draft horses. (A hinney, which has less commercial value, is produced from a stallion (male horse) and a female donkey, called a “jenny.” The word “hinney” comes from its parents – a horse and a jenny.)

Other crossbred animals

Artificial insemination has been used to crossbreed camels and llamas with the goal of producing a larger quantity of quality llama wool. Mankind has created such interesting creatures as ligers, crossbreeds of male lions and tigresses, tiglons (sometimes called tigons) from male tigers and lionesses, leopons (male leopards and lionesses), wholpins (whales and dolphins) and geeps (goats and sheep). Most of these have resulted in limited, if any, commercial value, although it was thought by some that they might.

Crossbreeding animal species is one of the prohibitions of the Torah when it declares behemtecha lo sarbia kil’ayim (Vayikra 19:19). It is one of the unusual mitzvos that even a non-Jew is required to observe (Rambam, Hilchos Melachim 10:6).

The prohibition is only to create the crossbreed; one may use a mule or any other crossbred animal. However, not only is it prohibited to crossbreed a horse with a donkey, it is even forbidden to attempt to breed a mule or hinney with either a donkey or a horse (Mishnah, Kil’ayim 1:6). In fact, it is rare that such an attempt will produce offspring, although it is claimed anecdotally that this can happen upon occasion. Nevertheless, someone who attempts to crossbreed them violates a Torah prohibition.

Crossbreeding of plants

Crossbreeding of plants, or, as it is usually called, cross-fertilization or cross-pollination, is when one pollinates the flower of one species with pollen from a different species, to produce offspring with some characteristics of each. Many fruits have been developed this way, although I want to share that a nectarine is not a crossbreed of a peach and a plum, as often mistakenly thought. A nectarine is an ancient variety of peach (Prunus persica) that has a smooth skin. Botanists consider it to be the same species as peaches.

What is interesting is that, in the discussions about kil’ayim in the Torah, the Mishnah and the writings of Chazal, nowhere does it say that it is prohibited to cross-pollinate from one plant species to another. This does not mean to say that there is no prohibition of kil’ayim germane to trees or plants. Quite the contrary, there are three such prohibitions min haTorah. They are referred to as kil’ei zera’im, kil’ayim in plants; kil’ei hakerem, kil’ayim in vineyards; and kil’ayim in trees, usually referred to as harkavas ilan. But, as we will soon see, none of these three prohibitions has anything to do with crossbreeding.

Kil’ei zera’im

Kil’ei zera’im is planting two or more different species of grains, vegetables or other edible herbaceous plants in close proximity. Exactly what defines “close proximity” is a very complicated halachic topic, and depends on factors such as the shape and size of the vegetable patch, and what variety of produce one is planting. We should note that, from a botanical point of view, planting two species in close proximity will not cause hybridization because it does not affect the genetic makeup.

This mitzvah applies only in Eretz Yisroel. Thus, someone in chutz la’aretz may plant his backyard garden with a wide variety of vegetables without any halachic concern, whereas in Eretz Yisroel someone planting a garden patch must be very careful to keep the different species separate.

Kil’ayim in a vineyard, kil’ei hakerem

Kil’ei hakerem is the prohibition against planting grains or vegetables in, near, above or below a vineyard. Again, this forbidden planting will not affect the genetic makeup of any of the plants involved. It is also clear that this was not the concern in halacha as we see from many of the halachic details. Here is one example: Although it is prohibited to plant grains or vegetables near a vineyard, there is a way to permit it by separating the vegetable patch from the vineyard with a halachic wall between them. For example, if one places two poles and a wire across the top, a tzuras hapesach, between the vegetable patch and the vineyard, it is permitted to plant vegetables right next to the vineyard (Eruvin 11a). This is similar to what we do when we construct an eruv to permit carrying on Shabbos. It is quite clear that, botanically, the tzuras hapesach does not accomplish anything to prevent the mingling of the species. Yet, with the tzuras hapesach, it is permitted to plant the crop; without the tzuras hapesach, it is a Torah prohibition to do so! This certainly cannot be explained on a scientific basis.

Even one grapevine is problematic near a crop plant, so care must be taken even in the home garden. For example, a pot with herbs or a vegetable under a trellised grapevine could forbid the grapes and the produce of the pot!

Unlike other forms of kil’ayim, the produce of kil’ei hakerem is forbidden to use.

The prohibition of planting grains or vegetables in a vineyard applies in chutz la’aretz, but only miderabbanan (Kiddushin 39a).

Harkavas ilan – grafting trees

The laws of kil’ayim also prohibit grafting one species of tree or plant onto the wood stock, or lower trunk, of another species. Although a town dweller may feel that this is a rare occurrence, in fact, contemporary plant nurseries and tree farmers usually graft branches of a species that produces delicious fruit onto the hardier stock of a different species.

For example, most peach and nectarine trees are produced by grafting a peach or nectarine branch onto the stock of a hardier tree, such as an almond. Someone who performs this, either in Eretz Yisroel or in chutz la’aretz, violates a Torah prohibition whether he is Jewish or not (Rambam, Hilchos Melachim 10:6). Most authorities rule that one may not own, water or prune a kil’ayim tree, whether or not it is in Eretz Yisroel or in chutz la’aretz (Shulchan Aruch Yoreh Deah 295:7 and Piskei Teshuvah).

However, many observant Jews purchased agricultural properties that contained kil’ayim trees and did not cut down those trees. Was there any justification for their actions? Numerous halachic responsa discuss what was apparently a widespread practice in the eighteenth and nineteenth century. Whereas most poskim rule that these Jews violated the halacha, some authorities justify the practice of owning these trees, at least in chutz la’aretz (Shu’t Chasam Sofer, Yoreh Deah #288; Aruch Hashulchan, Yoreh Deah 295:17-18).

Because so many trees are grafted nowadays, someone who owns a fruit tree should have a horticultural expert check whether its stock is from the same species or not. Often, even a non-expert can detect if a tree was grafted onto a different species by simply scrutinizing the tree. If the bark somewhere near the bottom of the tree looks different from the upper part of the tree, this indicates that the upper part of the tree was grafted. Often one can see a line separating the grafted scion from the rootstock, or a difference in thickness between the top and bottom. Before purchasing a new tree at a nursery, examine the trunk carefully for signs of grafting.

The prohibition of planting vegetables and other edible crops together applies only in Eretz Yisroel, whereas grafting trees applies equally min hatorah in chutz la’aretz and in Eretz Yisroel.

Although planting and caring for a kil’ayim tree is forbidden, the fruit from such a tree is permitted. Thus, one may purchase fruit in a market without worrying about kil’ayim.

Esrogim

Although space does not allow us to discuss this fascinating topic, there is a huge amount of halachic literature discussing the very common instance of using an esrog from a tree that was grafted onto a non-esrog tree. Most authorities rule that this esrog may not be used to fulfill the mitzvah on Sukkos.

Conclusion

Rav Hirsch (Vayikra 19:19) explains that the root word ke’le means to keep or hold something back, and that the plural form kil’ayim is similar to yadayim or raglayim and means a pair. Therefore, the word kil’ayim means to pair together two items that should be kept apart. This is to teach us that although we are given the world to develop, we must follow the rules that Hashem established for us to do so.