2019 ASHS Annual Conference

Vermicomposts are stabilized organic matter produced by interaction of earthworms and microorganisms. It has been well documented that their use in horticulture as organic amendment, as substitute or additive, for greenhouse and field crops increases growth and yield and suppresses pests and diseases. The production of its liquid counterpart commonly referred to as ‘teas’, used either soil drench or spray, have produced similar results on a variety of greenhouse and field crops. However its utilization and effects in hydroponics systems are still unknown. Low concentrations of vermicompost teas, produced from food wastes, at rates of 1.6% and 3.2% for lettuce and 0.14%, 0.28% and 0.56% for tomatoes were investigated as additive and supplement in static hydroponic systems. Vermicompost teas significantly increased lettuce yields when concentrations of nutrient solutions were reduced to 25% and 50% of the recommended full rate for nutrient solutions compared to treatments without vermicompost teas. Even lower concentrations of vermicompost teas increased tomato yields significantly as a supplement in reduced nutrient solutions of 50%. The presence of a combination of trace amounts of plant hormones such as auxins, cytokinins, gibberellins and humic acids in vermicomposts teas are likely the responsible factor that increased yields of lettuce and tomato in static hydroponics systems with lower concentrations of nutrient solutions.