How Often Should You Fertilize Tomato Plants?

Whether eaten fresh, cooked or canned, tomatoes are a versatile and tasty fruit. Fertilizing the tomato plants at the correct time helps yield the largest harvest. Tomatoes are low-calorie, rich in vitamins C and A and provide lycopene that may be helpful in preventing certain cancers, according to the University of Missouri Extension website.

Fertilize the tomato plant about one or two weeks before the first fruit ripens. Repeat the fertilization two weeks after you pick the first fruit and then again one month later.

Test the soil before fertilizing. This tells you which nutrients the soil is lacking. Tomatoes prefer a soil with a pH of 6.5 to 7. Work a timed-release fertilizer into the top 6 inches of the soil before planting the tomatoes. Once the proper level is obtained, treat the tomatoes with a maintenance fertilizer at 1 lb. per 100 square feet.

Tomatoes grow best with a balanced fertilizer with equal amounts of phosphorus, nitrogen and potassium. For instance, too much nitrogen results in a leafy plant with little fruit. Avoid the use of lawn fertilizers. Use a fertilizer product that is formulated for tomatoes or a complete garden fertilizer when preparing the soil. Use a water-soluble fertilizer once the plant begins to produce fruit.

Plant your tomatoes in areas with full sunlight. Areas away from trees and buildings offer the highest yields. A well-drained soil is important to prevent blossom rot or root rot. Tomato plants require a consistently moist soil. Stick your finger into the top 2 inches of soil. If dirt sticks to your finger it is moist enough. Mulch such as straw, pine needles, grass clippings, compost, shredded bark and leaf mold help conserve the moisture in the soil.