Feeding tomatoes
It is necessary to fertilize the garden before planting tomatoes. Apply the fertilizer again when fruit first sets. From that point on, an additional fertilization (sidedress) every week to 10 days is recommended. Plants grown on sandy soils should be fertilized more frequently than those grown on heavy, clay soils. A general sidedress fertilizer recommendation is one to two tablespoons of a complete fertilizer scattered around the plant and worked into the soil. If using a fertilizer high in nitrogen such as ammonium nitrate or sulfate, reduce the rate to one tablespoon per plant.