1. Q. When should you bed out sweet potato roots for slip production?
A. To produce slips, sweet potato roots should be laid on their sides in hotbeds about a month before the nighttime temperatures stay above 60 degrees F. Cover the sweet potato roots with 2 inches of moist sand and keep the hotbed between 75 degrees and 80 degrees F. When the sprout develop, remove them with a twisting tug. Additional transplants (slips) will form from the bedded sweet potatoes if left in place.
2. Q. I want to grow a few rows of sweet potatoes in my garden. How do I get seed or plants?
A. Sweet potatoes are started from transplants or vine cuttings rather than from seeds. Transplants, also called slips, usually grow from bedded roots. A vine cutting is 10- to 12-inch section cut from a vine growing in the field. Home gardeners can produce a limited number of slips or sections of vine by placing a sweet potato bud side up in a jar of water and placing the jar in a sunny location. Vines produced can be cut into sections and planted.
3. Q. What causes sweet potato roots to be long and stringy?
A. This condition is caused by high fertility. The edible portion of the sweet potato plant is a storage root. Luxurious growing conditions cause vigorous vinme growth and result in poorly-developed stringy roots. Maturity and variety also affect the texture of sweet potatoes.
4. Q. How do you know when sweet potatoes are mature and ready for harvesting?
A. Sweet potatoes can be harvested at any stage of maturity. They require 100 to 140 days from planting to maturity depending on variety. Harvest sweet potatoes before the first killing frost because cool conditions can physiologically damage roots.
5. Q. How should sweet potatoes be handled after harvesting for long-term storage?
A. Gently. The tender skins bruise easily. Any damage to the roots can cause considerable decay in storage. After harvesting, dry the sweet potatoes for 2 to 3 hours. Then, spread them out in baskets lined with newspaper. Place them in a dry area where the temperature will remain 80 degrees to 85 degrees F. for 10 days to 2 weeks. After this curing period, place them where the temperatures will range from 55 degrees to 60 degrees F. with a relative humidity of about 85 percent. Sweet potatoes treated this way will store for several months. Remove any roots that show signs of deterioration or decay.
6. Q. Is there a difference between sweet potatoes and yams?
A. Yes and no. In the southern United States, some sweet potatoes are advertised as yams, for example, Louisiana Yams. However, these are all sweet potatoes with the scientific name Ipomoea batatas. The true yam which is native to tropical regions is an unrelated plant with the scientific name Dioscorea batatas. The true yam is also called a Chinese Yam or Chinese Potato. True yams are not grown as food crops in the continental United States.
7. Q. When I harvested my sweet potatoes, they were rough and the surface was cracked.
A. This can be caused by two things. One is fluctuating moisture levels within the soil; and, other is root knot nematodes. If nematodes are suspected, check the part of the root closest to the plant for small necrotic lesions in the sweet potato. If nematodes are found, use the resistant variety Jewel in future plantings.
8. Q. After I dug my sweet potatoes, I found as much as one- half of each sweet potato covered with a black, necrotic scab which decays rapidly.
A. This is sweet potato scurf and is caused by a soilborne fungus. It is controlled by growing sweet potatoes in acid soil. Also, the use of disease-free slips and rotating crops helps prevent the disease.
9. Q. How do I control sweet potato weevils?
A. There are no chemicals currently cleared for control of sweet potato weevils. Certified weevil-free sweet potato slips, rotation and removal of allcrop residue and weeds which might serve as winter hosts for the sweet potato weevil is the best method of preventing weevil damage.