Organic vegetable crop production in controlled environments using soilless media

Organic vegetables produced in greenhouses and other controlled environments may fill a unique market niche as consumers demand local, high vegetables year round. However, limited technical information supports these production systems and more research is needed to provide recommendations for appropriate substrate mixes and nutrient management. Compost can be used as a substitute for peat-based media, and research results vary widely based on feedstock, compost method, and proportion used in mixes. Most studies consider compost in terms of peat-substitute or replacement and not as a source of fertility in soilless systems. Common challenges in using compost in soilless media are due to immaturity of the compost, poor water holding capacity, and unbalanced salinity and pH. It is possible to certify organic soilless production systems; however, the National Organic Program (NOP) of the U.S. Department of Agriculture has not yet provided clear rules and requirements supporting these systems. The objective of this article is to review the literature on soilless organic vegetable production, summarize results from the more widely studied topic of vegetable transplant production, and point to future research for organic agriculture.