Gardening in Gwinnett: Tomatoes produce abundant fruit with proper care

Tomatoes are the most popular vegetable plant grown. No garden would be complete without them since they require relatively little space for large production. Each plant, if properly cared for, yields 10 to 15 pounds or more of fruit.

Tomatoes are warm season plants that must be planted after all danger of frost has passed. They can be grown from seed, or, preferably, from transplants.

How many tomato plants should you plant? That depends on how many tomatoes you want to care for. A few, well-cared for plants can produce better quality fruits in higher numbers than many that have been neglected. Tomatoes need full sun, and at least one inch of water per week. They prefer well-drained soil heavily amended with organic matter such as compost and manure, and should be fertilized every four weeks with a 10-10-10 balanced fertilizer.

That will help with clay soils and will help the sandy soils hold water. The addition of organic matter increases the plant's ability to absorb water and calcium. Place some pine bark or pine straw mulch around the plants to keep moisture in the soil and to control weeds.

Tomatoes can develop roots all along their stems, so plant them deeply to form a strong root system. Prune out any suckers arising from the roots or the nodes, and remove branches and leaves touching the ground. The plants tend to grow tall and heavy, and will fall over. Stake the tomato plants with wooden stakes, tie the plants to a fence, or use tomato cages. Prune them to one or two main stems. Harvest the fruits when they have fully ripened on the vine.

Often, gardeners grow their tomatoes in cages to keep the fruit and leaves off the ground. One advantage of wire cages is the plants produce heavy foliage cover, which reduces sunscald of the fruit. Space the cages out at least three feet apart for good air circulation.

Many different varieties of tomatoes exist. They come in all sorts of shapes, sizes and colors. Determinate tomatoes grow in a more compact bush form and produce most of their fruits at the same time. Indeterminate varieties set fruit clusters along the vine and bear continually all season long. The small, cherry tomatoes are an example of indeterminate tomatoes.

Some varieties have been bred to have resistance to various diseases to which tomatoes are susceptible to. The plants are not immune to the diseases, and good cultural practices are a must. Resistance is listed on the plant label using these abbreviations: V for Verticillium Wilt, F for Fusarium wilt, N for Nematode, TSW for Tomato Spotted Wilt virus and T for Tobacco Mosaic Virus. Also, tomatoes are inundated with insect pests such as whiteflies, hornworms, aphids, and certain caterpillars. Insecticidal soaps control many pests, and pesticides with Bt (Bacillus thuringiesis) are useful in controlling some caterpillar pests.

Another common disorder of tomatoes is blossom end rot, where the fruit is a dark, sunken water-soaked area at the blossom end of the fruit. The cause is low calcium concentration in the fruit, but more often is the result of the plant being under stress due to lack of water followed by excessive soil moisture. Maintain the soil pH between 6.2 and 6.8 and supply calcium through applications of dolomitic limestone.

Avoid drought stress by using mulch and providing a deep watering once or twice a week. Do not overfertilize with excessive nitrogen. Overwatering can lead to a condition called leaf roll.

Using proper cultural practices and planting disease resistant varieties will help in the production of healthy, tasty tomatoes in the garden. For questions regarding growing tomatoes, contact the Extension office.

Timothy Daly is an Agricultural and Natural Resource Agent with Gwinnett County Extension. He can be contacted at 678-377-4010 or via e-mail at timothy.daly@gwinnettcounty.com