Benefits of vermicompost as a constituent of growing substrates used in the production of organic greenhouse tomatoes

Abstract

Six individual growing substrate components were selected. From the individual components, 35 growing substrates were constructed. Preliminary analyses, which included pH, electrical conductivity, and macro- and micronutrient concentrations, combined with environmental and cost implications were conducted to identify which substrates had the appropriate properties for growing tomatoes. From the 35 combinations, four growing substrates were chosen as having preferred properties required for organic greenhouse tomato production. A 22-week growth experiment was performed to determine if any of the selected substrates could improve the marketable yield of tomatoes when compared with rockwool (RW) under greenhouse conditions. The greenhouse crop used for this experiment was Lycopersicon esculentum 'beefsteak' tomato, cultivar Matrix F1 Hybrid. Within the experiment, Forterra RoyalGRO1 (GRO 1; coconut coir/vermicompost) and Forterra Royal GRO 2 (GRO 2; aged pine bark/ coconut coir/vermicompost) attained significantly higher marketable yields per plant compared with the plants grown in RW. A similar trend was seen in the incidence of Blossom End Rot (BER) with GRO 1 and GRO 2 having reduced numbers of BER incidences per plant when compared with RW. In conclusion, the addition of vermicompost to organic growing substrates is beneficial for tomato growth and yield.