It takes skill and ingenuity to raise blemish-free flavorful tomatoes and protect them from insects, diseases and other pests. Here's how to handle existing problems and prevent new ones.
This is a common problem, so we'll deal with it first. The first sign is a water-soaked spot near the blossom end of the fruit. This spot becomes brown or black and may enlarge until it covers a third to half of the fruit. As the spot grows, the tissues shrink and the surface becomes dark, leathery and often sunken.
Sometimes, blossom-end rot occurs when tomato plants have grown rapidly during the early part of the season and then are subjected to prolonged dry weather as the tomato fruits are developing. Other times, the damage occurs after long periods of extra rainfall. Research also indicates that extreme fluctuations in soil moisture and excessive applications of high nitrogen fertilizer aggravate this disorder.
The basic cause of blossom-end rot is a lack of calcium, so ensure an ample supply. Test your garden's soil pH before planting. If it's less than 6.8, spread ground lime before setting out the tomato transplants. Some gardeners even mix a handful of lime in the hole at planting time.
Water regularly so tomato plants receive a uniform supply of moisture. Keep the soil evenly moist but not extremely wet. Spread a 2 inch blanket of mulch over the roots to conserve moisture. Use grass clippings, compost or weed-free straw, replenishing as needed.
If blossom-end rot is already occurring, mix one tablespoon of calcium chloride per gallon of water and spray the foliage two or three times a week as the tomatoes are developing. Do not spray for the entire season, as it may injure the foliage.
Cracking – Tomatoes often crack after rainy periods and high temperatures that favor rapid growth. They are most likely to crack when they have reached full size and are turning color. Cracks blemish the fruit and often create points of infection.
The best way to avoid cracking is to plant resistant varieties such as Early Girl, Jet Star, Roma, Pilgrim and Heinz 1370. Also water regularly to keep soil moisture uniform throughout the growing season.
Blossom Drop – Tomato plants often develop beautiful blossoms that mysteriously fall off. This problem is often temperature-related. Some varieties may drop their blossoms when night temperatures fall below 55° while high day temperatures above 90° and night temperatures above 75° may also cause blossom drop. To prevent it, plant resistant varieties, keep the soil evenly moist and avoid using high nitrogen fertilizers during the early stages of plant growth. Also watch for signs of early blight or bacterial spot that may cause blossom loss.
Sunscald – Tomatoes get sunburn just like people. At first, a yellowish-white patch appears on the side of the tomato facing the sun. The damaged area gets larger and becomes grayish-white as the tomato ripens.
Prevent sunscald by training tomatoes in cages where the leaves shade the fruit (which delays ripening). On staked plants, leave some foliage to protect the ripening tomatoes. Also, control early blight and other diseases that cause tomato plants to lose their foliage.
Pests – Watch carefully for problems and always identify the pest before attempting to treat it. For help, take a sample to your Southern States dealer for identification and advice on control measures.
See your local Southern States dealer for all the seeds, seedlings and products you'll need to grow healthy, delicious tomatoes.