Sweet potatoes, rich in vitamin A and touted for their nutritional value, are often confused with yams. A true yam is a tropical plant, and an entirely different species from the sweet potato. When cultivated ornamentally, sweet potatoes grow as ground covers, in baskets or containers. Related to the morning glory, some varieties are trailing vines while others are bush varieties, ideal for growing in limited spaces. Sweet potatoes need a long period without frost to fully mature. When sweet potatoes are stored, new roots (called slips) develop. Planting slips is a common way of growing sweet potatoes.
Select an area with light, sandy, shallow soil. Sweet potatoes prefer a well-draining soil with a pH between 5.5 and 6.5. Rich soil will produce an abundance of foliage, yet an inferior crop of sweet potatoes. Schedule planting in the spring, after all danger of frost has past.
Turn the soil, going about 6 inches deep.
Scatter a 2-foot band of 5-10-10 fertilizer in rows, spacing the rows 3 to 4 feet apart. Use at a ratio of 1 lb. of fertilizer for every 12.5-foot row. Mix the fertilizer into the soil. Don't fertilize after the initial preparing of the soil.
Make a ridge (between 4 to 8 inches high) down the center of the each row by pushing the soil from the exterior of the row.
Plant the sweet potato slips on the top of the ridge, spacing 12 to 18 inches apart. About 4 inches of the slip should be planted in the soil, with one or two leaves above the soil line, and the rest buried.
Water well after planting, and keep evenly moist until they show signs of new growth. Sweet potatoes require less irrigation than most vegetable crops.
Water during an extended drought, yet do not water 3 or 4 weeks prior to harvesting the sweet potatoes. Harvest in the late fall, or when the tops blacken from the first frost.