If you planted sweet potatoes this summer, it’s time to harvest them—and there’s another step you need to take before you bring them into the kitchen. Here’s everything you need to know about how to plant, grow, harvest, and cure sweet potatoes at home.
Sweet potatoes are somewhat under utilized in home gardens, and that is a shame. These tasty members of the morning glory family are easy to grow, thrive in hot temperatures, and are capable of producing incredible yields. It is true that they require a fairly long, hot growing season and a substantial amount of space, but the payoff is a bumper crop in late summer or early fall with very little work beyond planting.
How to Plant Sweet Potatoes
Unlike regular potatoes, sweet potatoes grow from transplants, also called slips. Sweet potato slips are produced by year-old sweet potatoes in hot beds at large specialty farms in mid to late spring. They usually come in bundles of 25, which is enough to produce about two bushels of sweet potatoes. Plant them after the soil has reached 70 degrees Fahrenheit, and all danger of frost and cool weather well past.
There are many varieties on the market, including some really cool heirloom sweet potatoes of all different colors: white, golden, orange, and even purple. Their growing seasons vary between 90 and 120 days, so be sure to buy a variety that will mature before cool weather arrives in fall. ‘Beauregard’ is one of the most widely grown, because it matures in 90 days and handles slightly cooler temperatures better than some of the others. ‘Georgia Jets’ is another fast grower known for heavy yields.
Centennial Sweet Potato Slips, 12 for $21.95 from Burpee
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Sweet Potatoes Need Full Sun
Sweet potatoes should be planted in full sun, between 12 and 16 inches apart within rows that are separated by six feet. Till the soil deeply to promote good root development, and apply a starter fertilizer before planting. With a garden rake, work the soil up to a low ridge six inches high and 12 to 14 inches across, the full length of the row. To plant, use a garden trowel to open a slot in the soil. Insert the slip up to the first set of leaves, and firm the soil around it. Water well after planting. Sweet potatoes need about an inch of water per week, from two or three waterings.
The slips may look rough at first, but they quickly grow new leaves. In a couple of weeks they begin to grow vines across the ground. Let them run all over the garden bed. Wherever the stems touch the ground they root in, and can produce additional sweet potatoes. Dense foliage will ultimately shade the garden soil, nearly eliminating weed competition. If the runners go out of bounds, simply trim them back to within the borders of the bed.
Harvest with Care
There are often no visible indicators that sweet potatoes are ready to harvest. So, around the expected harvest date, begin looking for well developed tubers. If the roots on the selected plants are filled out well, it’s time to dig. Begin by removing the vines to expose the soil and the swollen areas where sweet potatoes are hiding just below the surface.
Begin digging at one end of the bed, at least a foot away from where the first slip was planted. Although large roots grow at the site of the slip, substantial secondary roots grow all over the place. Use a spade or garden fork to methodically dig up the entire bed, being careful not to damage the tubers. Brush off excess soil, but do not wash them. While harvesting, separate tubers that are large and undamaged from smaller, and/or damaged tubers. Both groups are usable, but the first group will hold up much better in storage.
Hutzler Garden Colander Harvest Basket, $31.93 from Home Depot
Haul your harvest in from the garden in this easy-to-clean colander basket.
Cure Sweet Potatoes to Prepare Them for Use and Storage
If you cook and eat a fresh sweet potato, you’ll be unpleasantly surprised. It will be starchy and bland. The flavor develops after harvest during a two to three week curing process. Commercial growers use climate controlled storage facilities that expedite the process. Home gardeners can use what they have at their disposal.
Curing heals any injuries to the surface of the potatoes, and helps them convert starch to sugar. The ideal climate for curing sweet potatoes is 80 to 85 degree temperatures, 90 percent humidity, and excellent air circulation. In this environment, curing is finished in about 10 days. In a hot environment, the potatoes can be packed in shallow crates and left in a shed or garage for a few weeks. Other possible curing locations include greenhouses, hot beds, or simply under a loose sheet of plastic out of direct sunlight.
The harvest is ready to use and store when the skins appear dry and firm, and all cut and scrapes have healed over. Move them to a cool, dry, dark location such as a basement or root cellar. Sweet potatoes store best in temperatures between 45 and 50 degrees with average humidity and good ventilation.
Check out some sweet potato recipe ideas for inspiration on using your harvest.
Header image courtesy of Aniko Hobel / Moment / Getty Images