LAUSR

Abstract The use of vermicompost water extracts (teas) in horticulture to increase plant growth and yield and suppress pests and diseases, is well documented. However, its utilization and effects in hydroponics systems are 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.