Evaluation of Fish Biosolids as a Growth Media Component for Organic Tomato Transplant Production

Interest among consumers is increasing for the availability of organically produced fruits and vegetables. Seafood demand is increasingly being met by fish raised using aquaculture methods that provide fish excretory products that can meet organic standards for nutrient sources for organic vegetables. We conducted an experiment in a glass greenhouse to evaluate fish biosolids as a growth media component for organic tomato transplant production. We compared the fishbiosolids treatment to several different organic fertilizers along with a commonly used inorganic slow-release fertilizer (Osmocote). All treatments used a target N concentration of 400 mg/L incorporated into the substrate and we also included fish biosolids treatments of 200 and 800 mg/L. Plant performance was montiored for 5 weeks starting with commercially available 2-week old seedlings. Results showed that the 800 mg/L fish biosolids treatment compared very favorably with the inorganic Osmocote treatment at the conclusion of the trial. The 800 mg/L fish biosolids treatment exceeded the Osmocote treatment for chlorophyll content and for leaf number for the first 4 weeks of the 5 week trial. Grower management protocols could further improve seedling performance by providing additional top dressings of fish biolsolids or fish effluent waters as the plants age.