When to Harvest Sweet PotatoesSweet Potatoes may be dug in early fall as soon as the tubers reach a good size. But don't hurry. The longer Sweet Potatoes stay in the ground, the larger and sweeter they get. It's best to wait until the leaves start to yellow or frosty weather is approaching. (Should the vines get frosted, it's important to harvest immediately.) Harvest Sweet Potatoes from right at the base of the plant, just barely under the ground. If the soil is relatively loose, you can simply brush it away to reveal the tubers. If your soil is heavier, use a garden fork to dig down and loosen the soil, then lift the tubers up out of the ground. When a Sweet Potato first comes out of the ground, its skin is very thin and it can be easily nicked or bruised. Handle the tubers as gently as eggs, transferring them carefully to a bin that's been lined with burlap or an old blanket. Move the potatoes out of the sun into a warm, dry location and lay them out in a single layer, so the skins can dry for a week or so.How to Cure Sweet PotatoesIf you plan to use your Sweet Potatoes within a month or two, it isn't necessary to cure them. Simply air-dry the tubers for 7 to 10 days at 75° to 80ºF. For long-term storage, Sweet Potatoes should be cured at 90ºF and 85% humidity for 5 to 7 days. Home gardeners with a modest-sized harvest can do this quite easily in an oven. Put a thermometer on the middle rack, and then place a light bulb on a cord inside the oven, run the cord out the door and plug it in. Close the door almost all the way. After an hour, check the temperature and either open the door a little wider or change the bulb wattage to achieve exactly 90°F. Load the Sweet Potatoes onto the oven racks so they're not touching. Put a pan of water in the bottom of the oven and begin the 5-day curing period. Once your Sweet Potatoes have been cured, nestle them into a box, allowing plenty of room for good air circulation. For storage, an air temperature of 55° to 60°F is perfect, with a humidity level of 75% to 80%. A cool, dry basement usually works fine.Enjoying Sweet Potatoes All WinterOur affection for Sweet Potatoes grew when we learned they are almost twice as nutritious as any other vegetable. High in vitamin C as well as calcium, folate, potassium and beta-carotene (which the body converts to vitamin A), Sweet Potatoes are also an excellent source of dietary fiber, protein and iron. And, though they are sweet, Sweet Potatoes have half the glycemic load of white Potatoes. They are a good carb that our bodies digest slowly, so we feel satisfied far longer than with most other foods.