A healthy tomato plant produces plump, well-shaped tomatoes. These tomatoes have smooth skins and even coloring, and are free of cracks, dark spots or soft depressions. If your tomatoes have any of these markings, they may have suffered from any one of the many conditions that plague tomato fruit. You can identify tomato fruit problems by appearance and texture. Tomatoes with holes in them have usually been ravished by birds or bugs, but other symptoms are usually indicative of physiological conditions.
Check tomato plants frequently. As the tomatoes begin to grow, check the bottoms of the fruits as well as the tops. The top and side of a tomato may appear healthy, but if the underside is exhibiting a dark brown spot that feels soft, your tomato is suffering from blossom end rot. This condition occurs from a lack of calcium.
Remove all tomatoes that show symptoms of blossom end rot. Discard as waste; do not add them to your compost. Maintain even watering practices and improve the soil with side dressings of calcium nitrate fertilizer. Continue to check remaining tomatoes as they grow.
Look for small cracks or crevices on the underside of the tomatoes. If you see cracks or splits in which the area within the crack is brown and crusty in appearance, the tomatoes may be affected by catface.
Protect young flowering tomato plants with row covers early in the season if temperatures are still cool. Catface occurs when night temperatures drop below 50 degrees Fahrenheit. Providing protection may aid in preventing this condition.
Watch for sunscald as the temperatures rise. This condition affects those tomatoes that may not be fully protected from the sun by foliage. The condition appears as a white or yellowish spot on the surface of the fruit. Dried and wrinkly looking, the area may be surrounded by a kind of yellowish ring or halo. Avoid sunscald by using protective sunscreens for your plants during the hottest parts of the day.
Check tomatoes for even coloring as they begin to ripen. If a tomato exhibits patches gray or yellowish in color during the maturation stages, hold the tomato in the palm of your hand. It may feel lumpy and distorted.
Press gently against the discolored area with your thumb. If the patch feels hard or dried out, it may be a symptom of gray wall. Gray wall affects the outer appearance of the tomato as well as the interior. The cause is unknown, but may be due to lack of nutrients in the soil. Remove all tomatoes displaying gray wall symptoms and supply the plants with nutrients through side dressings of fertilizer.