South Carolina's climate is conducive to growing many types of vegetables. When sowing seeds, knowing predicted first and last frost dates of the growing season, how long it takes for plants to mature, and whether they thrive in cooler or warmer weather is essential for successful gardening. U.S. Department of Agriculture hardiness zones 7 and 8 encompass the state. Three geographic zones, including the northwestern Piedmont, central and coastal regions, help gardeners decide when to plant. Certain varieties grow in winter while others thrive in the state's subtropical warmth.
Pole bean seeds need soil temperatures to be above 50 degrees for germination to occur. In South Carolina, successive plantings happen April 15 to 30 and July 15 to 25 in the Piedmont region, April 5 to 10 and July 20 to 30 in the central region, and March 20 to 30 and Aug. 1 to 10 along the coast. Plant pole beans in soil that is moderately fertile and well-drained. Plants require full sun to grow well.
Carrots are cool-season root crops that do not tolerate very hot weather well and therefore can be planted earlier and later than warm-season vegetables such as beans and tomatoes. Sow carrot seeds March 1 to 15 and July 1 to 30 in the Piedmont region, Feb. 10 to 28 and Aug. 1 to 15 in central South Carolina, and Dec. 15 through Jan. 15 and Aug. 1 to 15 on the coast. Plants need consistent watering, full sun and deep, loose, well-drained soil to grow well. They must be thinned to two to three inches between plants to give them room to grow.
Like carrots, radishes are also cool-season root vegetables that grow best in well-drained, moist, deeply tilled soil and full sun. They are one of the quickest growing plants, maturing in about four weeks, and do not take up much garden space. Plant seeds Feb. 15 to March 15 and Sept. 1 to 30 in the Piedmont region, Feb. 1 through 28 and Sept. 1 through Oct. 25 in the central region, and Jan. 1 through March 1 and Sept. 1 through Nov. 1 along coastal areas.
Summer squash, a warm-season vegetable, produces rapidly once flowers become pollinated and fruit forms. They should be picked when fruit is smaller and tender, before the rind hardens. In South Carolina, seeds are planted from April 15 through May 15 and July 1 to 20 in the Piedmont region, April 1 to 20 and Aug. 1 to 15 in the central region, and March 20 through April 10 and Aug. 10 to25 on the coast. Plants grow best in full sun and well-drained soil. Regular watering is required.
Leaf lettuce, a cool-season crop, grows well in all seasons but summer in South Carolina. Plant seeds from March 1 to 15 and Aug. 15 to 25 in the Piedmont region, from Feb. 1 to 28 and Aug. 15 to 25 in the central region, and Dec. 20 through Feb. 5 and Aug. 15 to 25 along the coast. Full sun and well-fertilized soil that drains well and is free of large clumps are best for growing leaf lettuce. Thinning of seedlings to four to six inches between plants is necessary to avoid overcrowding.