Uprooting kila'im during Shemitah
Question
Do I need to uproot Kila'im in my garden during the shemitah year?
Answer
"On the first of Adar they make a public announcement about the shekels and concerning kila'im" (Mishnah Shekalim 1:1).
In the Land of Israel, it is forbidden to sow diverse species in close proximity (annuals, including vegetables, legumes, and grains). This is the prohibition of kilei zera'im. There is also a special prohibition of kilei hakerem, interplanting near/under vineyards, which is even more severe and applies abroad as well.
After the winter rains, self-seeding plants sprout up in fields or vineyards, and it is incumbent upon field and vineyard owners to uproot them to avoid the prohibition of kila'im, sowing diverse species in close proximity. This is why in the times of the Mishnah, in regular years, the public was reminded of this obligation on the first of Adar.
Does this obligation apply during shemitah?
The obligation to uproot kila'im does not apply in ownerless fields. For this reason, plants that sprout in home gardens, fields, and even vineyards need not be uprooted since the land is ownerless.
However, in fields or vineyards sold through heter mechirah, such plants need to be uprooted. This is because the kila'im prohibition applies even to land owned by non-Jews in the Land of Israel.