Healthy Listed below are some of the most common tomato maladies and what you can do about them. Consult your local extension service for help diagnosing these and other problems. It affects both green and ripe tomatoes, and is most often caused by a fluctuating moisture supply that results in a lack of calcium in the plant. Don't overfertilize with nitrogen.
Plants supported by cages tend to be less susceptible to blossom-end rot than staked plants.
Sunscald first appears as light, shiny blistered areas that eventually rot. It develops when tomatoes are suddenly or continually exposed to direct sunlight. The problem is most common on plants that lose a lot of foliage either by excessive pruning or from disease. In very hot, sunny locations plant determinate varieties with dense foliage or grow indeterminate tomatoes in cages without pruning them. Cracking around the stem end and along the sides of ripening tomatoes often results from rapid fruit growth, often caused by a quick change in soil moisture, especially when wet weather follows a dry spell.