12-5771 Mitzvah N-107
Negative Mitzvah 107– This is a negative commandment: do not sow two kinds of seeds in a field.
Hafetz Hayim – As Scripture says: “you shall not sow your field with two kinds of seed” (Lev. 19:19). In lands other than Israel, a Jew is permitted initially, from the start, to sow two kinds of seeds together. As for mixed kinds of trees, which means grafting an etrog tree onto an apple tree, or anything similar, it is forbidden in the other lands as well. So too, it is forbidden to graft a tree onto a vegetable or a vegetable onto a tree, even in other lands. However, with both mixed kinds of seeds and mixtures of trees, even though a violation of the law is committed thereby, their produce is nevertheless permitted to be eaten, even by the one who did the forbidden act. As for mixtures of a vineyard (which means planting grain in a vineyard), it is forbidden to sow them, eat their produce or derive any benefit from them – in other lands, by the law of the Sages; and in the Land of Israel, by the law of the Torah.
Here we have to think like a farmer. There are so many acres of land that are ready to produce food. Clearly we want to use as much of the land as possible. By planting a mixture of different crops, we can not only feed our family but also have a hedge against the failure of any one crop. The problem is that the Torah forbids us from certain kinds of planting. We can plant one area with wheat, one area with barley and one with oat. But we can’t mix these grains together in one field. The problem here is not grafting, we are not talking about hybrid grains. This is just not a proper way for Jews to plant grains. The law applies only in the Land of Israel.
Grafting trees is the issue in the second part, since it does not matter if you plant different trees close to one another. Here the problem is creating hybrid fruits or vegetables. While Jews should not be doing these kinds of plantings, there is, significantly, no punishment for those who do the grafting nor is there a prohibition against using the hybrid fruits. The prohibition applies both in Israel and in other lands.
In a vineyard, one might think to use the space between the vines to grow grain. After all the vines are above so the grain could grow below. This is also forbidden. And if it is done, then the fruit of both grain and vine are forbidden to be eaten, sold or used in any way that the grower could derive a benefit.
So the question is, “Why?” Why are we forbidden to mix seeds? This is one of three laws in this one verse (Leviticus 19:19) which includes the prohibition of mating cattle with different animals and wearing cloth of two different materials (linen and wool). These laws are part of the priestly legislation that are very concerned with keeping things pure and preventing “impurity”. This law of “mixture” falls under a category of laws, in Judaism, called “Hukkim” or “laws that have no apparent logical explanation”. We are commanded to obey these laws, not because we understand them, but because God gave them to us. Etz Hayim, the Bible commentary published by the Rabbinical Assembly, USCJ and JPS, notes that, in Conservative Judaism, we accept hukkim when they do not affect us morally. When they do affect our moral sense, we reserve the right to challenge and change the law; challenging the Torah to be morally consistent in its laws (p. 697 comment on verse 19). These laws about “mixture” don’t seem to have any moral issues associated with them so they stand as written.
There are number of commentators who try to find meaning in these “unexplainable” laws and their answers are interesting, midrashic in nature, explaining after the fact why such a division of species is a good idea. The Torah seems to be teaching that we have limits in how we can change nature. The Sages may limit these mixtures by location and species but the fundamental meaning behind them is unknown. Modern anthropologists have tried to make sense of these laws in Judaism and in other cultures with mixed results (eg: Mary Douglas, Purity and Danger). The reasons behind these laws still remains unclear and when we take up farming, we are bound by these purity laws.