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 1 to 2 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 1 tablespoon per plant. When tomatoes have more vine than fruit, you are being told to cut back on fertilizer.

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