Tomato

Tomatoes (Solanum lycopersicum) are a popular staple in Southern vegetable gardens. Tomatoes are warm-season plants that grow best at 70 to 80 °F during the day and 60 to 70 °F during the night

Planting

Tomatoes (Solanum lycopersicum) are popular vegetable garden plants.
Zachary Boone Snipes, ©2017, Clemson Extension

Tomato plants may be started indoors from seed, or transplants may be purchased from a reputable garden center. If starting plants from seed, use a light soil mix and give the plants plenty of light. Tall, spindly transplants will result from low light levels. Supplemental light will be necessary unless grown on a sunny, south-facing windowsill.

Sow seed indoors six to eight weeks before the last frost date in your area. A week before transplanting, harden-off indoor-grown plants by exposing them to an increasing number of hours outdoors each day and reducing the watering frequency (but do not allow them to wilt). Initially, place the plants in bright, indirect sunlight under a tree or covered porch. The foliage of tomato plants will develop purplish veins as they harden off. For more information, see HGIC 1259, Starting Seeds Indoors.

Choose a well-drained site where tomatoes, peppers, eggplant, or potatoes have not been grown for at least three years. This will help in avoiding soil-borne diseases and nematodes. Transplant into the garden during the evening hours or on overcast days to reduce wilting.

Select stocky transplants about 6 to 10 inches tall. Space plants 24 inches apart on rows that are 3 feet apart. Set tomato transplants deep enough to expose only two or three sets of true leaves. If transplants become “leggy,” horizontal planting of tomato plants is an effective way to strengthen plants. Roots will form along the buried portion of the stem. Press the soil firmly around the transplants so that a slight depression is formed for holding water.

Recommended Planting Dates

Gardening zone map

Piedmont: Abbeville, Anderson, Cherokee, Chester, Chesterfield, Edgefield, Fairfield, Greenville, Greenwood, Kershaw, Lancaster, Laurens, McCormick, Newberry, Oconee, Pickens, Saluda, Spartanburg, Union, and York Counties.

Coastal Plain: Aiken, Allendale, Bamberg, Barnwell, Beaufort, Berkeley, Calhoun, Charleston, Clarendon, Colleton, Darlington, Dillon, Dorchester, Florence, Georgetown, Hampton, Horry, Jasper, Lee, Lexington, Marion, Marlboro, Orangeburg, Richland, Sumter, and Williamsburg Counties.

Fertilizing

A soil test is always the best method of determining the fertilization needs of the crop. Information on soil testing is available in HGIC 1652, Soil Testing. Follow the soil test results to maintain a soil pH between 6.0 and 6.5.

Apply lime and pre-plant fertilizer according to soil test recommendations. Lime is best applied and tilled into the garden at least 3 months before planting. Broadcast the fertilizer evenly and incorporate it into the soil by tilling or disking to a depth of around 6 inches. Working the fertilizer into the soil ensures that the nutrients are available to the plants when they are transplanted.

Side dress 1 pound of calcium nitrate (15.5-0-0) per 100 square feet (30 feet of row) three to four weeks after planting. On sandier soil, this may need to be split into two applications three to four weeks apart to reduce fertilizer losses to leaching. To avoid burning the roots, side-dress fertilizer 4 to 6 inches away from the plants. If fertilizer is broadcast, avoid burning the plant foliage by watering overhead after the application to wash fertilizer granules off the leaves.

Staking, Caging, and Trellising

A Florida weave trellis is a great way to keep tomato plants up and off the ground.
Justin Ballew, ©2020 HGIC, Clemson Extension

Because the tomato plant is a vine, staking, caging, and trellising are good ways to keep the plants and fruit up and off the ground. Being off the ground makes fruit easier to pick, easier to spray, and improves airflow around the plants, which is an important disease management strategy.

Use wooden stakes 6 feet tall and 1 ½ or 2 inches wide for staking. Drive them 1 foot into the soil about 4 to 6 inches from the plant soon after transplanting. Wrap heavy twine or strips of cloth around plant stems and attach to the stakes at every 10 inches of height.

Growing tomatoes in wire cages will allow air circulation and reduces the spread of disease.
Barbara H. Smith, ©2017 HGIC, Clemson Extension

For trellising, 6-foot stakes should be driven into the ground halfway in between each plant or every other plant on the row. Twine should then be run the length of the row on either side of the stakes and plants, looping around each stake for support. As the plants grow, another row of twine should be added about every 10 inches of height. This technique is known as the “Florida weave.”

Wire cages are popular because of their simplicity. Cages are more expensive initially but will last many years. Be sure cages have at least 6-inch spacing between the wires to allow adequate space to reach inside to harvest the tomatoes.

Pruning

A tomato sucker shown growing between the main stem and the branch.
Joey Williamson, ©2014 HGIC, Clemson Extension

Prune tomatoes to one or two main stems. A new shoot will develop at the junction of each leaf and the first main stem. If plants are trained to two stems, remove all other shoots, called suckers, weekly to maintain these two main stems. Shoots are easy to pinch off by hand.

If tomato plants in wire cages are pruned, once is usually enough. Prune to three or four main stems. Tomatoes pruned just once will develop a heavier foliage cover, educing sunscald on fruits. However, humidity may be higher because of the greater foliage density, which may allow foliar diseases and fruit rots to spread more easily.

Types

There are hundreds of tomato cultivars available, categorized by plant growth habits and fruit types.

Plant growth habits:

• Determinate tomato plants grow to a certain size, set fruit, and then decline. Most early-ripening tomato cultivars are determinate and will not produce tomatoes throughout a South Carolina summer.
• Indeterminate tomato plants continue to grow and produce for an extended season. Fruit production may continue until the first frost. Most heirloom tomato cultivars have an indeterminate growth habit.

Fruit Types:

• 

  Super Sweet 100 have smaller fruit that are often used in salads.
  Barbara H. Smith, ©2017 HGIC, Clemson Extension

  Cherry and grape tomatoes are small, very sweet tomatoes that are often used fresh in salads.

• Beefsteak tomatoes have large fruit that are commonly sliced and eaten fresh. These tend to be very juicy and are great for tomato sandwiches.
• Roma or plum tomatoes have medium-sized, oblong fruits with very meaty interiors and few seeds. Romas are a favorite for cooking and canning.

Recommended Cultivars

The following tomato cultivars are known to perform well in South Carolina gardens. Numerous other cultivars may perform well, so feel free to experiment, but do so cautiously.

Always choose cultivars with disease resistance. Fusarium wilt is a common disease that can destroy an entire tomato crop. Many varieties are resistant to this disease. The letters F, FF, or FFF after the cultivar name indicate resistance to races 1, 2, and 3 of Fusarium wilt. VFN means the plants are resistant to Verticillium wilt, Fusarium wilt, and root-knot nematodes; VFNT adds tobacco mosaic virus resistance to the list. Tomato spotted wilt virus resistance is indicated by “TSWV.” Most heirloom cultivars have little to no disease resistance.

Harvest & Storage

Depending on the cultivar, it takes 52 to 90 days to reach the first harvest. Flavor is best when the fruit is picked fully vine-ripened but still firm. If immature (green) fruit is harvested, do not refrigerate, as this inhibits ripening. Instead, ripen them at 70 °F. Light isn’t necessary for ripening green tomatoes. Green tomatoes can be stored at 50 to 70 °F for one to three weeks. Ripe tomatoes can be stored at room temperature (70 °F) or in the refrigerator for 4 to 7 days. However, refrigeration can reduce flavor and cause the tomatoes to develop a mealy texture.

Insect and Disease Pests and Physiological Disorders

For information on tomato diseases, physiological disorders, and disease-resistant cultivars, see HGIC 2217, Tomato Diseases & Disorders. For information on insect pests, see HGIC 2218, Tomato Insect Pests.

For information on blossom end rot, see HGIC 2217, Tomato Diseases & Disorders.
Justin Ballew, ©2019 HGIC, Clemson Extension

Originally published 06/99