Kilayim, Chapter Two, Mishnah Seven
This mishnah begins to discuss the issue of adjacent fields planted with different types of species. In the previous mishnah we learned that there must be a separation between fields or rows planted with different species. In todays mishnah we learn that sometimes it is okay to have fields of different species adjacent to one another.
We should note that according to the rabbis kilayim is only prohibited from the Torah (deoraita) when one mixes seed in ones hand and sows them together. Areas with different species that are adjacent to one another are only prohibited by the rabbis (derabanan) because this looks like kilayim. Under certain circumstances, when it doesnt look like kilayim, this is permitted.
1) If the point of an angle of a wheat [field] overlaps into a barley [field], it is permitted because it looks like the end of his field.
2) If his [field] is of wheat, and his neighbors is of another species, he may sow [next to the border] some of the same species [as that of his neighbor].
3) If his field was of wheat and that of his neighbors was of wheat, he may sow next to him a row of flax, but not a row of any other species.
a) Rabbi Shimon says: it is all the same whether he sows flax or any other species.
b) Rabbi Yose said: even in the middle of one’s field it is permitted to check ones field with a row of flax.
Section one: In this case, a point of an angle of a field planted with wheat enters into, or according to other interpretations, is adjacent to, a field planted with barley. Imagine a triangular field, where one of the corners is next to a square field. Since it looks like the angle is the end of the wheat field, there is no problem of kilayim here.
Section two: If his field was of wheat and his neighbor had a field of another species such as barley, he may sow barley next to his neighbors field. This doesnt look like kilayim in his own field, because the row of barley looks like part of his neighbors field.
Section three: In this case both his field and his neighbors field are of wheat. He is allowed to sow one row of flax between the two fields. Everyone knows that one row of flax is so negligible that no one would plant in this manner in order to grow flax for use. Rather it is readily apparent that the only reason to plant the flax was to check the fertility of his field, whether in the future his field is appropriate for sowing flax. Since every one knows that his purpose in planting this furrow was not for the produce, it does not look like kilayim.
According to Rabbi Shimon it doesnt make a difference what type of seed the single row consists ofin all cases it is recognizable that he is only planting in order to see if his field can grow this type of species. It seems that according to Rabbi Shimon people dont plant rows of single species in order to grow the produce, rather just to check the fecundity of the field.
Rabbi Yose holds that one may do so even within ones own field. That is, one can plant one row of flax in the middle of a wheat field (or any other type of field), because it is apparent that the row of flax was put there only in order to check the field, whether it can sustain flax. Anyone seeing such a set up will understand that this is not kilayim.