Do not sow two kinds of seeds in a field
“Do not sow your field with two kinds of seeds” Vayikra 19:19
In lands outside of Israel a Jew is permitted from the outset to sow two kinds of seeds together.
Mixing kinds of trees- meaning grafting a citron onto an apple tree or similar things is also forbidden outside of Israel.
It is forbidden to graft a tree onto a vegetable or a vegetable onto a tree even outside of Israel.
Even though a violation is committed with both mixtures of seeds and mixtures of trees their produce is permitted to be eaten, even by the one who did this forbidden act.
It is forbidden to have mixtures in a vineyard – forbidden to sow them, eat the produce or derive any benefit from them.
The Scribes said this applies outside of Israel, and in Israel it is forbidden by Torah law.