Hydroponic produce should not be classified as organic because it’s not grown in soil, a lawsuit against the USDA alleges.

The federal suit, filed March 2 by a group of organic farmers and the Center for Food Safety, seeks to force the USDA to stop letting food made from hydroponically grown plants be labeled organic. It argues that because federal rules state that organic crops must foster “soil fertility,” plant grown without soil can’t possibly qualify. Hydroponic plants are grown with roots submerged in water or exposed to the air, with nutrients added to the water or applied through spraying.

The issue was triggered by a report on the USDA website that stated, “The USDA organic regulations do not currently prohibit hydroponic production.” The lawsuit charged that USDA took this position without opening the matter to public input.

Bloomberg News quoted a representative of a hydroponic farm as saying, ““Changing the rules now would limit the amount of organic produce available to the public – just as the public is demanding more organic produce.”