Kilei zera'im in hydroponic systems
Question
If you’re growing vegetables in a hydroponic system, does kilayim apply? Could you grow tomatoes, lettuce, herbs and cucumbers next to each other in the same larger system? Their roots would likely touch at some point. Above the surface it would look like they are divided.
Answer
Rabbi Dr. Yoel Friedemann
If each is in a separate container that can be removed together with the plant, no distancing is necessary. It's also not a problem if the roots or leaves eventually touch. From the pictures you sent me, it seems that this is the case. If they are not in separate, removable containers, proper distance should be maintained between different types of annual plants.
For the appropriate amount of spacing for each vegetable, see our handy kilei zera'im calculator, here.