Organic hydroponics: A U.S. reality challenging the traditional concept of “organic” and “soilless” cultivation

Authors: DI GIOIA, FRANCESCO - Pennsylvania State University; Rosskopf, Erin

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2021
Publication Date: 9/30/2021
Citation: Di Gioia, F., Rosskopf, E.N. 2021. Organic hydroponics: A U.S. reality challenging the traditional concept of “organic” and “soilless” cultivation. Acta Horticulturae. https://doi.org/10.17660/ActaHortic.2021.1321.36.
DOI: https://doi.org/10.17660/ActaHortic.2021.1321.36

Interpretive Summary: The demand for organic produce in the United States continues grow annually. The market demand has resulted in the development of new organic systems that are not traditional, soil-based systems. Although there is some question regarding the acceptability of organic hydroponic systems, the National Organic Program standards allow for certification of these systems if they meet all other organic requirements regarding seed and planting materials and organically-acceptable inputs for plant nutrient management. There are many research needs related to these systems, some of which could be aimed at defining the biological component of these systems in order to better evaluate the systems relative to soil-based organic production practices.

Technical Abstract: The continued growth of the US organic food market is capturing the interest of many growers and entrepreneurs producing and marketing specialty crops, including those investing in “soilless” cultivation systems. The high demand for and consequent high value of certified organic produce makes it compelling to invest in organic systems, including those that are hydroponic. These systems are considered hybrid cultivation systems in which organic-derived nutrient solutions and/or growing media are used to feed crops grown in soilless cultivation systems (SCS). Unlike in other countries, the US Department of Agriculture (USDA) National Organic Program (NOP) allows certification of “organic” crops produced in hydroponic, aquaponic, and aeroponic systems that are compliant with the U.S. Organic Regulations. This organic certification of such hybrid system is supported by the USDA Agricultural Marketing Service, although in 2016, the Hydroponic and Aquaponic Task Force of the National Organic Standards Board (NOSB) examined the alignment of “organic hydroponic” or “bioponic” systems with the USDA organic regulations andin 2016 recommended that aeroponic systems be excluded from organic certification. Today, while certified organic farms adopting organic hydroponic systems are a reality in the US, there is still significantcontroversy concerning their compatibility with the traditional organic concept. On one side, traditional organic growers contest that it is not possible to produce healthy food without a healthy soil; on the other hand, organic hydroponic proponents claim that their soilless cultivation procedures are compliant with the USDA organic regulation and that, not only they are producing healthy, organic crops, but their cultivation systems are also more sustainable than traditional soil-based organic production systems. While providing a brief overview of the subject and of the concept of bioponic production systems adopted in the US, the objectives of this work are to: i) examine the challenges and potential opportunities offered by organic hydroponic cultivation systems in comparison to both traditional organic and soilless cultivation systems, and ii) identify current knowledge-gaps and research priorities, so that future research-based knowledge may contribute to clarify the parameters that define each system.