How to Grow Sweet Potatoes
Learn Methods to Plant and Harvest this Orange Fleshed Vegetable
Nov 11, 2008
Sweet Potatoes are native to Central and South America where the weather is warm most of the time. They are cultivated commercially in most southern states in the US. You can, however, grow some varieties in the north as long as the temperature stays up in the 60s F toward the end of the growing season. (Sweet potatoes like it hot in the 80s or 90s).
Sweet potatoes are tender vegetables that are related to the morning glory. They grow on vines that cover the soil and set roots along their journey in the garden. There are also Bush varieties that have short vines and work better in areas with limited space.
Planting Sweet Potatoes
Don’t expect to plant sweet potato from seed. You can get “slips” at the local nursery. Slips parts of a sweet potato vine. A common science project for school children entails placing a sprouting sweet potato suspended with toothpicks in a glass of water. The vine grows out the top and the roots grow in the water. The vines that come out at the top are usually white and then turn green with leaves. These are the slips and will produce roots and vine out. You can grow your own from a sweet potato but it is a good idea to purchase slips instead of doing it yourself. This will make sure your plants will be as disease resistant as possible. If the slips you have taken from the potato or have purchased start to wilt just put them in a glass of water and they should perk right up.
Plant the slips directly in the garden in early summer when the ground temperature reaches 70 degrees. Create a wide raised ridge about 8 inches high in the garden. Plant the slips 12 to 15 inches apart in the high part of the ridge. As mentioned before, sweet potatoes love the heat so it is beneficial to use black plastic mulch to keep the ground warm. Allow about 3 to 4 feet between rows as the vines need lots of room.
You won’t have to worry much about weeds since the vines will choke out anything that tries to grow in them. Water regularly and fertilize with a 5-10-10 water soluble fertilizer every 3 weeks once they start growing. Most sweet potatoes take 100 to 110 days from start to finish. Stop watering regularly during the last 3 to 4 weeks before harvest.
Harvesting and Storing Sweet Potatoes
Harvest before the first frost hits your area. Use a fork or spade to carefully dig below the ridge. Be careful as you don’t want to bruise or spear the potatoes. Move closer to the roots until they are exposed. Dig underneath to pull the potatoes out. If the potatoes are still in the ground when the first frost comes to your area, it will limit the storage time you can keep your potatoes. Once the potatoes are harvested, cut the vines and clean the garden area as soon as possible to deter pests.
Sweet potatoes need to be cured. In the perfect situation potatoes should dry on the ground for about 2 to 3 hours and then put into a warm 85 degree room for 10 to 14 days. They will not cure at a temperature below 70 degrees so make sure to put them in the warmest room in the house.
After curing your sweet potatoes should be stored in a cool place such as a root cellar. They will normally last 10 days. You can put them in the refrigerator but they tend to taste different than if stored in a natural setting. Use them to create main and side dishes, desserts, or other recipes.
Varieties of Sweet Potatoes that you can grow in the North
There are about 400 varieties of Sweet Potato. The following are varieties that can be harvested in 100 days, so are possible to grow in the North, and are pretty disease resistant:
- Beauregard has orange flesh and coppery skin. It is very disease resistant and a proven producer.
- Centennial has orange skin and flesh, keeps well and is very disease resistant.
- George Jet has orange skin and flesh and is a bit more cold tolerant than some of the other varieties.
- Jewell has orange flesh and produces a particularly good yield. If you want a lot of sweet potatoes, this is your variety. It keeps well too.
- Vardaman goes 110 days and is a compact bush variety for those who do not have a large growing area. The flesh is orange but the skin is light yellow. The foliage when first growing is purple.
The Sweet Potato Yam Controversy
Many say that yams and sweet potatoes are the same thing, but that is not true at all. Most canned yams are actually not yams at all but sweet potatoes. In the mid 20th century sweet potatoes were introduced to America with the name of Yam in order to distinguish them from the white fleshed potato that was already known and used in that time. Sweet Potatoes belong to the Morning Glory (Convolvulaceae) family while the Yam belongs to the Dioscoreacea family. Yams will only grow in the tropics and were originally and still are grown in Africa.
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