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Title: Supplemental fertilizers for organic greenhouse soil media

item Webber Iii, Charles
item ROBERTS, BILLY - Oklahoma Agriculture Experiment Station

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2009
Publication Date: 5/1/2010
Citation: Webber III, C.L., Roberts, B.W. 2010. Supplemental fertilizers for organic greenhouse soil media [abstract]. In: Proceedings of the Oklahoma Academy of Science. November 6, 2009. Ada, Oklahoma. 89:94-95.

Interpretive Summary:

Technical Abstract: The consumer’s perceptions that organic food tastes better and is healthier are two major factors driving the increasing demand for organically produced crops in the U.S. It was necessary to develop organic certification to provide consistent standards across the U.S. for the benefit of producers, processors, wholesalers, retailers, and consumers. All components entering into the organic crop production system must be approved for organic use, including the seed, soil media, and fertilizer used in transplant production. Research was conducted to determine whether the addition of supplemental fertilizer to an organic soil media enhance seedling growth. The factorial experiment included 4 fertilizer rates (5-4-4, 6-2-2, 7-3-7, and 0-0-0 N-P-K) added at 1% by weight prior to planting tomato seeds (‘Florida 47’) and 2 liquid fertilizer rates (0.4% and 0%) added at 3 weeks after planting (WAP) with 6 replications with 6 plants per replication. Adding fertilizer prior to planting produced significantly greater plant heights and fresh weights at 3 and 5 weeks (WAP) compared to the control (0-0-0). Although there were few height differences among 3 fertilizer treatments at 3 WAP, the addition of 0.4% solution of a fish and seaweed fertilizer at 3 WAP resulted in a significant height and dry weight increase at 5 WAP for the 6-2-2 fertilizer treatment. To produce suitable tomato transplants supplement fertilizer was required at a level of 1% by weight of a 6-2-2 N-P-K organic fertilizer, which was further enhanced by applying a 0.4% solution of a fish and seaweed fertilizer at 3 WAP. Further research should investigate additional organic soil media, fertilizer sources and rates, and crops.