Book
Kilayim כלאים
a tractate of the order of Zeraim
Four different prohibitions are gathered into one tractate because they share a root: do not mix what the Creator separated. The Mishnah works out at what distance different seeds may be sown so that it does not count as mixing, and what to do about a vineyard.
The last chapter is on shaatnez, wool with linen. This is one of the "chukim"—laws without a stated reason; the tractate itself seeks no reasons, being occupied with measures and distances.
Order: Zeraim. There is Gemara only in the Jerusalem Talmud.
On the timeline
Related
Sources
Chazal: Mishnah, Talmud, midrash, Zohar
- Mishnah Kilayim 1:1 — which kinds count as different
- Leviticus 19:19 — the three prohibitions of mixing
Basis: Talmud and midrash.