On February 6, 2018, the Organic Farmers Association wrote and sent a letter to the Honorable Sonny Perdue, U.S. Secretary of Agriculture, regarding the National Organic Program’s (NOP) statement that “Certification of hydroponic, aquaponic and aeroponic operations is allowed under the USDA organic regulations, and has been since the National Organic Program began.”点击这里阅读完整的信。