How to Grow Sweet Potatoes

The sweet potato is a tropical vegetable that thrives in the long, hot summers of North Carolina, but it can be grown wherever it will have 150 frost-free days to develop. Once planted, sweet potato sprouts will produce their nutritious, flavorful roots with little care.

1. Select a sweet potato variety  Depending on the variety, sweet potatoes can produce a different colored and flavored flesh. Some are sweeter than others and colors can range from pale to deep orange. Choose a variety that will work with your climate and will suit your needs. For a complete comparison of sweet potato varieties, refer to our variety table.

2. Grow Your Sprouts Start your sprouts a month before warm weather takes hold and when night temperatures get no colder than 60 degrees. You can also buy sprouts from one of our seed producers.

  • Suspend a sweet potato on toothpicks in a container; cover half of the sweet potato with water. This will produce several sprouts. Larger quantities can be grown by placing several sweet potatoes on a bed of sand and covering them with a 2-inch layer of moist, sandy soil.
  • In about a month, the sprouts will grow 8-10 inches and produce several leaves. This is the optimum length for transplanting to a garden. Remove the sprouts by giving them a twist or cutting them off with a knife.

3. Transplant Your Sprouts Sweet potatoes take a better shape when grown in well-drained, sandy, loamy soil. Prepare the soil by tilling well and applying an 8-8-8 fertilizer at the rate of 2 pounds per 25 feet of row. Push the softened, fertilized soil into a foot-wide, flat-topped ridge row that is 8 inches high.

Plant sprouts 9 to 10 inches apart in the center of the ridge row and at a depth of 3 inches with at least 2 plant nodes underground and 2 or more leaves above ground. Water well immediately after transplanting.

  • Fertilizing: Roots will begin to form in 30 to 45 days and need nitrogen, phosphorus, and potash for optimum growth. Thirty days after transplanting sidedress, place fertilizer 2-3 inches to the side of the plant, with an 8-8-8 fertilizer at the rate of 2 pounds per 25 feet of row.
  • Insect Control: Be sure to follow all label directions, restrictions and precautions. Use a foliar spray of Sevin or Malathion at the rate of 2 tablespoons per gallon of water every 7 to 14 days as necessary.
  • Weed Control: Uncontrolled weeds can decrease sweet potato yields as much as 100 percent. A bit of gentle weeding is all that is needed. Be careful not to injure the shallow roots.

4. Harvest Your Sweet Potatoes Sweet potato roots are harvested 90-120 days after transplanting or immediately after a frost has blackened the tops of the plants.

  • Check roots for maturity. A mature sweet potato sprout will have 4 to 5 roots of varying sizes, but the majority should have a 1-3/4 inch diameter and be 3-9 inches in length. You can check for maturity by gently lifting the sprouts and their roots, or the sweet potatoes, out of the ground with a shovel. Make sure they do not become detached from the vine. If not mature, lower back down and cover with soil.
  • Dig for sweet potatoes. With gloves and a shovel, carefully remove sweet potatoes from the soil. Handle them carefully as their skin is thin and will bruise easily. Do not leave the sweet potatoes exposed to direct sunlight for more than 30 minutes or they will sunscald and be more susceptible to rotting during storage.
  • Curing process. Away from direct sunlight, spread the sweet potatoes out to dry for several hours. Once dry, put them in a newspaper-lined box and leave them in a dry, ventilated area for 2 weeks. This process will convert the sweet potatoes’ starches to sweet sugar. Once cured, store in a cool, dry place until ready to cook. Sweet potatoes can be stored for up to 10 months with little reduction in quality.
© 2014 North Carolina Sweet Potato Commission | Site created by: CRT/tanaka