What Causes Garden Fresh Tomatoes to Have Tough Skins?

Variety

• Some hybrid varieties, such as Burpee's Long Keeper are bred for long storage and are most often used by commercial growers. Fruit from these plants have naturally thick skins. When choosing tomatoes, avoid those that are described as "storage" tomatoes.

Growing Conditions

• Too much water causes blossom-end rot or cracking, while too little water may stunt growth or cause small fruits with thick skins. Tomatoes nipped by frost may develop thick skins or water spots that eventually rot. Keep soil evenly moist throughout the growing season and pick tomatoes if a frost is predicted. Throw away small, green tomatoes that will never ripen, but store large green or slightly red tomatoes in a dark, cool area until they ripen.

Diseases and Problems

• Most diseases and problems cause spots, mold or rot on tomatoes, rather than tough skins, with the exception of sun scald. Sun scald occurs when tomatoes receive too much bright sunlight due to defoliation because of disease or excessive pruning. The injured area may develop a yellow, white or brownish scab that later turns soft and begins to rot. Avoid overpruning so tomato fruits have some leafy protection from the sun. In intense heat, shield tomato plants with landscaping fabric.

General Guidelines

• Plant tomatoes only after the last frost, when daytime temperatures are predictably above 75 degrees F. Planting them earlier may stunt growth or cause the fruits to be deformed. Apply a liquid fertilizer once or twice during the season, according to package directions and cage tomatoes or stake them to control their growth.