I am currently growing certain things… and I’m looking to start on etrogim… my question is can one grow hydroponic etrogim? The reason for that is I’d be able to control every step of the etrog’s grows by feeding it the right nutritions and in so eliminating any blemishes and so forth making it mehudar etrogim…. does that make sense? And would it be kosher? If you could please get back to me. Many thanks.
The question of hydroponic growth of etrogim is discussed by poskim with regard to an “atzitz she-eino nakuv” (an un-holed pot).
Some authorities, such as the Aruch HaShulchan (645) are lenient, but others are stringent (see Kitzur Shulchan Aruch 136:2), and the Chayei Adam (152:3) [also cited in the Mishnah Berurah 649) writes that this is a matter of doubt.
Out of doubt, it is not recommended to grow etrogim in this manner.