Grape Vine Waste and Giant Reed Biomass Composts as Peat and Mineral Fertilizer Substitutes for Producing Organic Tomato Transplants

There is a need to develop and determine the efficacy of composts as growing and fertilization media in the production of organic tomato (Solanum lycopersicum) transplants. The use of composts was researched for organic tomato transplant production. Pre-germinated tomato seeds were planted in substrates of different concentrations (20%, 40%, 60% and 100%) of either grape vine-pruning residue or giant reed-biomass composts amended with or without perlite. The substrate pH and salinity as well as nutrient uptake by transplants increased with increasing compost percentage. Compost water wash removed mainly potassium. Emergence, growth, fresh and dry weight, as well as nutrient concentration, were compared with those of seedlings established in a commercial peat-based substrate. When substrates with a grape-vine-compost content of up to 40% were used, transplant fresh weight was similar to that obtained in the control substrate. Locally produced compost-based substrates provided a peat-free alternative for raising tomato transplants. Vegetable growers and especially organic growers will benefit from production and use of compost-based substrates for raising transplants.