3,034. A Mixed Species That Grew Spontaneously

Hilchos Kilayim 2:7

Let’s say that someone planted a certain species in his field, but when the crops came up he saw a mixed species there. If the mixed species covers 1/24 of the field’s area, he must gather it until he reduces its number because of the appearance of wrongdoing, since passersby might think that he planted the mixed species on purpose. This is so regardless of whether the mixed species that grew was (a) grain and legumes among grain and legumes or (b) gardening seed among grain, legumes and gardening seed. If the amount of the mixed species that grew was less than 1/24, it need not be reduced.

Hilchos Kilayim 2:8

The previous halacha applies when there’s reason to suspect that the owner of the field would intentionally plant the mixed species. If it’s clear that such was not his intention, but it’s obvious that the mixed species grew on its own, then he need not reduce it.