How to Get Rid of Leather Leaf in Tomatoes

Transplant Carefully

• Careful transplanting of tomato seedlings is one way to avoid the development of leathery leaves. First, harden off young plants by gradually exposing them to the outdoors the week before transplant. Garden soil should be rich in organic matter to ensure good drainage, which tomato plants need. Do not plant young seedlings too deeply in the ground, and allow adequate spacing between tomato plants. Leave at least 24 inches between seedlings, and 36 inches for large vining indeterminate varieties.

Water Consistently

• Regular, consistent watering of tomato plants throughout the growing season can also help to eliminate problems with leather leaves caused by physiological leaf roll. Extended periods of too wet or too dry conditions may result in leaves curling upward, with a cigarlike appearance, and becoming leathery to touch. Growing tomato plants require 1 to 2 inches of water per week; during dry spells, mulching with straw, compost, paper or plastic helps to retain moisture.

Avoid Overpruning

• Leaf roll is even more likely to occur when dry soil conditions are combined with overpruning. Because of their bushlike growing culture, determinate and semideterminate rarely require any pruning. Indeterminate plants, on the other hand, can become too full or tall and thus may benefit from the careful removal of some side shoots or top branches. But when too many stems and shoots are removed, the development of leaf roll and leathery leaves becomes more likely. Caging indeterminate tomatoes greatly reduces the need for pruning.

Avoid Overfertilization

• Careful application of fertilizers is another step to ridding problems with tomato leaf roll. Before applying garden fertilizer, soil testing is recommended to ensure correct levels of nutrients are added to the ground. Fertilizers with lower ratios of nitrogen and higher levels of phosphorus and potassium are recommended to tomato growers, for example, ratios of 8-32-16, 6-24-24 and 10-52-17. The University of Missouri Extension recommends adding 2 tablespoons of soluble fertilizer to 1 gallon of water, and then applying 1 cup of solution around the roots of each seedling at planting.

Apply Herbicides Carefully

• Exposure to herbicides like 2,4-D produces the same signs of physiological leaf roll in tomato plants, including leaf rolling and thick leathery leaves, as well as deformed fruit. Because herbicide injury cannot be reversed, use weedkillers carefully and do not use grass clippings as mulch if the lawn has been treated for weed control.

Watch for Signs of Virus

• Viral infections are more serious concerns for tomato growers. One -- tomato yellow leaf curl virus – produces similar symptoms to physiological leaf roll. This fatal disease is transmitted by whiteflies and causes tomato leaves to curl upward but also stunts plant growth and produces yellow mottled leaves. Keep garden beds weeded to discourage insect pests and decrease likelihood of infection.