3,044. How Far to Space Two Different Types of Vegetable

Hilchos Kilayim 3:10

If a field was planted with vegetables and the owner wanted to plant a different species of vegetable in an adjacent field - even gourds (which require a lot of space) - he must separate six handbreadths by six handbreadths (about 2.25 square feet) between the two, regardless of whether the empty space stops in the middle of the fields or runs along their sides. If the space between them is smaller than this, it is prohibited to plant there but one is not liable to the penalty of lashes unless the plants are within one handbreadth of one another (about three inches).

Hilchos Kilayim 3:11

If grain was planted in one field and vegetables or gourds were planted in the other, one must separate between them an area sufficient to plant a quarter-kav (which, as we have said, is about 232 square feet).