3,033. Mixing Different Types of Seed Intentionally

Hilchos Kilayim 2:5

Pursuant to the previous halacha, let’s say that grain got mixed with flax seed. If there was 3/4 of a kav of seed per seah of grain,* one must reduce the volume of the flax; if less than that, one need not reduce it. This is because three seah of flax is typically planted in an area in which a seah of grain can be planted. Such calculations are made for every species of seed.

Hilchos Kilayim 2:6

The preceding halachos only apply when a person didn’t intend to mix the two species and he didn’t plan to plant the resulting mixture. If one meant to mix or to plant two species of seed, then it is prohibited to plant even one grain of wheat with an entire heap of barley. The same rules apply in all comparable cases.

*Note: a seah (about 2.25 gallons) is six kav.