Sweet Potatoes: A Long-Season Crop Worth the Effort

Sweet potatoes are a long-season, tropical vegetable grown mostly in southern states, but northern gardeners can succeed too.

About This Plant

Most varieties need at least 4 frost-free months. They thrive in heat—plants are very tender, can't take frost, and refuse to grow in cool soil. Best yields with night temperatures averaging 72°F. Grown from "slips" (sprouts) available at southern nurseries or by mail. If growing your own slips, start sprouting ~8 weeks before planting.

Site Selection

Choose a site with full sun and well-drained soil. Loosen soil to 12–15 inches and mix in a 2- to 4-inch layer of compost.

Planting Instructions

Unless soil is very sandy, raise planting bed 6–8 inches into a ridge ~1 foot wide. After frost danger passes and weather is warm (nights >55°F), set slips 12–18 inches apart along ridges or in rows 36–48 inches apart. Plant to depth of first leaves with several nodes underground. Firm soil, make a shallow depression around plant, and water generously for a few days.

Care

Control weeds by hoeing or mulch 4–5 weeks after planting. Deep water in hot dry periods to increase yields. If storing part of the crop, withhold extra water late in season. Contact your extension office for flea beetle controls.

In cool climates, protect vines from late-season frost—frost-damaged vines can transfer rot to roots.

Harvesting

Sweet potato vines don't die back like white potatoes. In hot climates with long seasons, check hills regularly and harvest at best cooking stage. Best to dig on a dry, overcast day or shade unearthed roots from sun. Dry on ground for a couple hours. Don't wash after harvest. Sort damaged/bruised potatoes to eat first.