Southerners and sweet potatoes are a match made in heaven. We love the tasty flesh; sweet potatoes love our long, hot summers. In fact, about 40 percent of the nation's sweet potato crop is grown in North Carolina. Unlike true potatoes (that hail from the Andes) or yams (from Africa and Asia), these thickened roots of tropical vines are native to the Caribbean region, most likely the Yucatan Peninsula. They are fat-free and high in fiber and vitamins A, C, and E. Sweet potato's botanical name is Ipomoea batatas; see Ipomoea for ornamental types.
More than 400 selections of sweet potato are grown; many heirlooms are still popular. Skin colors range from buff to pink to dark red. Flesh may be orange, yellow, white, pink, red, or purple. The following are just a few of the most popular selections.
'Beauregard'. Ready for harvest in 9095 days. Rose skin, orange flesh. High yields. Stores well. Originated in Louisiana.
'Bonita'. 90100 days. Tan to light pink skin, white flesh. High sugar content. Nematode resistant. Originated in Louisiana.
'Carolina Ruby'. 115 days. Ruby to purple-red skin, orange flesh. High yields. Heirloom.
'Centennial'. 8090 days. Red skin; deep orange, soft flesh. Very high yields. Widely planted.
'Covington'. 105115 days. Rose skin, orange flesh. High yields. Nematode resistant. Originated in North Carolina.
'Evangeline'. 100110 days. Rose skin, deep orange flesh. Very sweet and moist. Nematode resistant. Originated in Louisiana.
'Jewel'. 120135 days. Copper skin, orange flesh. High yields. Nematode resistant. Originated in North Carolina.
'O' Henry. 90 days. Creamy white skin, white flesh. High yields. More disease resistant than most other white sweet potatoes.
'Porto Rico'. 110 days. Pink skin, orange flesh. Average yields. Bush type; good for small gardens.
'Topaz'. 90 days. Copper-orange skin, orange flesh. Good yields. Nematode resistant.
'Vardaman'. 100 days. Yellow-orange skin, deep orange flesh. Delicious flavor. Bush type; good for small gardens. Originated in Mississippi.
'White Delight'. 100110 days. Purplish pink skin, white flesh. Good yields; good keeper. Nematode resistant. Originated in Georgia.
Sweet potatoes grow best in well-drained, acid soil (pH 5.86.2); sandy loam is ideal. Vining types can spread to 20 ft. and need plenty of room. Bush types are compact, spreading just 35 ft., and are better for small gardens.
Start with certified disease-free slips (rooted cuttings) obtained from a local or mail-order nursery. If Southern root-knot nematodes are a problem in your area, choose resistant selections. Plant in late spring when the soil has warmed to 70F. Before planting, mark off rows (3 ft. apart) and dig shallow ditches between them. Pile excavated soil onto rows to form planting ridges; this ensures good drainage. Work in a controlled-release, low-nitrogen fertilizer such as cottonseed meal or composted manure; too much nitrogen produces lots of leaves and small roots. Set slips into ridges so that only stem tips and leaves show aboveground. Space plants 1 ft. apart. Cover plants with row covers to keep out insect pests. To prevent a buildup of disease organisms in the soil, don't grow sweet potatoes in the same location two years in a row.
Harvest before first frost; if tops are killed by sudden frost, harvest immediately. Dig carefully to avoid cutting or bruising roots. Flavor improves in storage (starch is converted to sugar). Let roots dry in the sun until soil can be brushed off; then cure by storing 10 to 14 days in a warm (about 85F), humid place. Store in a cool, dry environment (not below 55F).