Tomatoes thrive with a well-balanced fertilizer, rather than one that's created for special conditions. Some fertilizers are higher in potassium or nitrogen to encourage green growth at the expense of fruit or flowers. Commercial or homemade compost is a balanced fertilizer. Cornell University College of Agriculture and Life Science recommends using compost every other week on tomatoes as a fertilizer side dressing.
Tomato plants grow well when homemade compost fertilizer is added to the soil before the tomatoes are planted. Tomatoes are "heavy feeders," which means they grow a lot in a short amount of time and require a large amount of nutrients. Homemade compost fertilizer is created from the combination of nitrogen-rich green materials such as yard waste, leaves and kitchen scraps; oxygen from the air; and water. The decomposition process creates fertilizer that is very rich in microorganisms. The microorganisms provide tomato plants with the nutrients they need to grow successfully.
Tomatoes grown with chemical-free compost fertilizers have increased nutrient value and more intense flavor. Read the labels on composts available at garden centers to be sure they are USDA organic. The U.S. Department of Agriculture's Organic Program certifies fertilizers and soil additives. There are strict guidelines for what constitutes the "USDA Certified 100-Percent Organic" label. Some commercially available tomato plant fertilizers use terms such as "Natural" even though they are not completely chemical-free.
Vermicompost fertilizer, which is created by worms, is ideal for strong tomato growth. Worm bins are easy to maintain in a small space. Compost created by worms in a worm bin contains five to 11 times more nitrogen, phosphorus and potassium than garden soil. These nutrients are the building blocks for healthy tomato plant growth. Redworms help break down food waste in the same way microorganisms do in the normal compost process, but the result is a more concentrated, nutrient-rich fertilizer.