Hydroponics

Hydroponics is a form of agriculture in which plant life is grown in liquids rather than in the soil. This is a result of the roots of such vegetation being able to absorb their essential nutrients by means of a water supply in which the needed vitamins are artificially introduced. It's not necessarily soil that is required for plant growth – merely specific nutrients which can be supplied by other mediums besides soil. Contrary to popular misconception, hydroponics is not a new form of agriculture. It had been used extensively in ancient times and even makes an appearance in the Talmud.[1] The development and popularity of hydroponics continue to make for some very interesting halachic questions.

Hydroponics is especially useful during the Shemitta year when planting and most other agricultural work is forbidden. Many Israeli farmers use hydroponics as a method which allows them to supply fruits and vegetables to the Israeli public without violating the prohibition on working the land during the Shemitta year. This is because produce grown hydroponically during the Shemitta year is not subject to any halachic restrictions and does not have the status of "Kedushat Sheviit", sanctified produce. So too, according to most authorities hydroponically grown vegetables are exempt from the teruma and ma'aser tithes which are only binding upon produce grown in the ground.[2] It is also noted that produce grown hydroponically is much more likely to be insect-free than produce that is grown in the ground. Finally, by purchasing hydroponically grown produce Israelis are able to continue supporting Jewish farmers during the Shemitta year.

Although the blessing normally recited upon vegetables is "borei pri ha'adama" it seems that reciting this blessing on vegetables which did not grow from the ground would essentially be a false statement. As such, most authorities rule that one is to recite the "shehakol" blessing when eating vegetables grown hydroponically.[3] This is similar to mushrooms upon which the "shehakol" blessing is recited even though they grow from the ground. This is because mushrooms actually receive their nourishment from the atmosphere, not from the ground.[4] There is a minority view, however, which rules that the blessing regularly recited on vegetables, "ha'adama", should be recited upon hydroponic vegetables, as well. This is because vegetables are instinctively identified with the ground and most vegetables today continue to be grown in the ground.[5] If one is unsure whether a certain vegetable was grown naturally or hydroponically, the "ha'adama" blessing should be recited upon it.[6]

On Shabbat it is forbidden to tend to growing produce in any way and hydroponics is no different. Therefore, it is forbidden to initiate hydroponic growth on Shabbat or to add nutrients or even water to a plant which is presently growing.[7] Similarly, one is not permitted to detach hydroponic produce on Shabbat, even for immediate consumption.[8] In order to avoid a number of halachic complications and uncertainties, it is best to use only earth-grown produce for the marror and karpas vegetables at the Pesach Seder.[9]

[1] Avoda Zara 38b.

[2] Zeriah 3:4 (R. Tukatchinsky).

[3] Chayei Adam 51:17; Yechaveh Daat 6:12.

[4] Berachot 40b.

[5] Shevet Halevi 1:205; Teshuvot V’hanhagot 2:149.

[6] Yechaveh Daat 6:16.

[7] OC 336:11.

[8] OC 336:5; Shemirat Shabbat K'hilchata 26 note 9.

[9] Pesachim 39a; cf. Mishna Berura 473:55.