| The consistent supply of fresh, healthy, local foods, in urban environments is often not feasible due to the lack of available space. Green roofs offer an alternative growing space to provide vegetable products to urban markets. However, adequate fertility to maximize plant growth is often lacking in green roof media, especially after several seasons of intensive production, since these media mixes contain only various gradations of expanded lightweight clay aggregate with about 4 to 5% organic matter. This research evaluated four fertilizer treatments applied weekly to 'Bush Champion II' tomato ( Solanum lycopersicum) grown in a three inch extensive green roof media mix on the Southern Illinois University campus. The fertilizer treatments evaluated were: (1) vermicompost tea (from coffee grounds; 12,600 mg/kg N), 2) Miracle-Gro fertilizer (16,100 mg/kg N), 3) Organic Miracle-Gro fertilizer (6,900 mg/kg N), and 4) no fertilizer (0 mg/kg N). Water was applied through drip irrigation daily and fertilizer treatments were applied in 1.9 L of water for each plant once a week from transplant to the end of harvest. Ripe tomato fruit were harvested eight times from June to August.;Plant vigor, chlorophyll content, and marketable yields were greater (P ≤ 0.05) when Miracle-Gro and Organic Miracle-Gro were used as the fertilizer source. Subsequently, the no fertilizer and vermicompost tea application resulted in less production as lower available nutrient content (especially N) in these treatments reduced tomato plant vigor and fruit yield. Although, the analysis indicated that the verimcompost tea had a relatively high amount of N, most was in the organic form and was not readily available for plant uptake. This study indicates that acceptable tomato yields can be achieved in a three-inch extensive green roof with adequate fertilizer applications. |
