Kilayim, Chapter 2, Mishnah 2. In the previous mishnah, the first of the chapter, we learned that in a mixture of two different kinds of seeds, the amount that is considered kilayim is calculated as a quarter of a kav of the minority seed mixed into a se'ah of the majority seed. Since there are six kavim in every se'ah, a quarter of a kav is one twenty-fourth, and that is the calculation we worked with.
Mishnah 2 comes to explain how this calculation applies to different types of seeds, whether smaller or larger.
"Bameh devarim amurim":
When does the calculation of a quarter of a kav to a se'ah, one twenty-fourth, apply?
"Tevuah bitvuah" - edible grains that became mixed with other edible grains.
"Kitnis bekitnis" - legumes that became mixed with other kinds of legumes.
"Tevuah bekitnis vekitnis bitvuah" - grain that became mixed with legumes, and legumes that became mixed with grain.
Even though the sizes of these seeds sometimes differ from one another, in general all of these edible items are treated by the Sages with a single calculation: one twenty-fourth.
"Ve'emes amru" - garden seeds that are not eaten:
"Ve'emes amru" - but in practice they said that there is an exception: "zironei ginah she'einan ne'echalin". These seeds are used for planting certain kinds of vegetables, where the vegetable itself is eaten but the seed is not eaten, unlike grain and legumes, where the seed itself is eaten. Regarding these it is stated: "mitztarfin echad me'esrim ve'arba benofel leveis se'ah" - their combining to the measure of one twenty-fourth is measured according to the amount that falls, meaning that is sown, in a beis se'ah.
The commentators explain the meaning of this: these seeds are very small, and they are not included in the broad category of grain or of legumes. Therefore we calculate the percentage of the small minority seeds relative to the majority seed, but not on the basis of a measure of a se'ah, since in that same field one would not sow a se'ah of such seeds, but a far smaller amount.
For example: if instead of a se'ah, which is six kavim, the amount one would sow of the ordinary seed in that field, of these seeds one would sow only a quarter of that - a kav and a half - then the measure of the minority seed is reduced accordingly: instead of a quarter of a kav, a quarter of that, meaning one sixteenth of a kav. It emerges that if one sixteenth of a kav of these seeds that are not fit for eating became mixed into a se'ah of wheat, even such a tiny percentage, far smaller than one twenty-fourth, already creates a problem, and one must be stringent.
The view of Rabbi Shimon: "Keshem she'amru lehachmir kach amru lehakel":
Rabbi Shimon says: "Keshem she'amru lehachmir" - as was explained, that with very small seeds sown in a limited quantity, twenty five percent of the amount in which an ordinary seed is sown in that field, we are stringent and consider it kilayim even when only a tiny percentage is mixed in with them - "kach amru lehakel", as in the following example.
"Hapishtan bitvuah":
"Hapishtan bitvuah" - flax seeds that became mixed with grain. Flax is sown in a large quantity: in a field where one normally sows a se'ah of grain, one sows three se'ah of flax in that very same area. Therefore it is stated that these seeds combine at the measure of one twenty-fourth of what falls in a beis se'ah, meaning according to the amount of them that falls and is sown in a beis se'ah.
What emerges from this is a great leniency: instead of being stringent, as with the small seed where a tiny percentage renders it forbidden, here the percentage is far greater than one twenty-fourth - three times the amount. In practice, instead of a quarter of a kav, one may mix in up to three quarters of a kav of flax seed into a se'ah, six kavim, of grain, of ordinary produce. And the reason is this: the amount of flax normally sown in that area is three times greater than the amount of the majority seed sown there, and therefore the calculation is likewise three times greater.
In summary: in this mishnah we learned that the calculation of one twenty-fourth, a quarter of a kav to a se'ah, was stated with regard to grain in grain, legumes in legumes, and grain and legumes in one another - all the edible items together. By contrast, with garden seeds that are not eaten, the measure is determined by the amount actually sown in a beis se'ah, and since they are sown in a far smaller quantity, a stringency results: even a tiny percentage of a mixture renders it forbidden. And Rabbi Shimon added that just as they said to be stringent, so too they said to be lenient - with flax, which is sown in a quantity three times as large, the permitted measure grows threefold, up to three quarters of a kav in a se'ah.