Sweet potatoes produce an ornamental vine that blooms similar to its close relative, the morning glory. Unlike the morning glory, the vine rarely blooms and instead the plant is grown for its edible tubers. Sweet potatoes do not tolerate frost, so they are grown as an annual in most gardens. They thrive in areas with long, warm summers as they take 130 or more days to reach maturity. Sweet potatoes are grown from slips, which are small transplants produced off the rooted tuber.
Prepare the garden bed for planting two weeks before starting the vine. Loosen the soil in a well-drained, full-sun garden bed to an 8-inch depth using a spade or power tiller. Pull the soil up into an 18-inch-wide ridge for each sweet potato row you are planting, as the ridge encourages the soil to warm more quickly.
Apply 3 lbs. of 10-10-10 analysis fertilizer per every 100 square feet of bed. Lay the fertilizer down next to each ridge.
Poke a hole in the ridge and place a sweet potato slip into the hole so it is about half buried. Firm the soil around it. Space each sweet potato slip 12 to 18 inches apart.
Water the slips immediately after planting, then approximately once a week thereafter. Supply 1 inch of water to the garden bed at each watering.
Fertilize the sweet potato vines a second time once they begin actively growing in midsummer. Apply a 10-10-10 analysis fertilizer per each 100 square feet of bed. Avoid getting the fertilizer directly on the vines, as it may burn or damage them.
Harvest sweet potatoes in fall before soil temperature drops below 50 F. Dig under the ridge with a spading fork, turning the soil over to reveal the potatoes. Separate them from the soil then spread them out in a dark, 80 to 85 F room to cure for two weeks prior to storage.