Kilei zera'im and hydroponics
Question
- Does the prohibition of kilayim apply to two types of vegetables grown using hydroponics?
- Assuming it does apply — in hydroponic cultivation, there is usually more than 12 cm between seedlings, although the tops of the leaves sometimes touch. What is the halachic status in such a case?
- What about cucumbers and similar spreading plants grown in such systems?
Answer
Shalom and blessings,
The kilei zera'im prohibition applies even in hydroponic cultivation, and the standard distancing requirements must be followed.
Therefore, if there is a space of a tefach and a half (roughly 13 cm), that is certainly sufficient.
As with all issues of kilayim, if the appropriate distance is maintained, we are not concerned about the mingling of the upper parts (leaves, stems).
Regarding spreading vegetables, the required separation distance should be maintained for them. However, in such cases, one can create a vertical separation at a height of 80 cm, which resolves the issue of spacing for spreading vegetables. For the appropriate amount of spacing for each vegetable, see our handy kilei zera'im calculator, here.
With blessings of Torah and the Land,
Rabbi David Eigner
Torah VeHa'aretz Institute
Note by Rabbi Dr. Friedemann:
If each plant is growing in a planter that is easily removable, this is considered a sufficient hekker, and distances are not necessary. The above applies when this is not the case and the plants are growing from different holes in one pipe, which means that it is considered one vessel.