Skip to main content
Good Growing

How Sweet It Is

Very often what grows in a garden are those fruits and vegetables we enjoy eating. Though, sometimes our gardens may exceed our appetites. After growing fifteen kale plants last year, my family determined, we probably could live off of two. And ten cherry tomato bushes were nine too many. One vegetable, my family does enjoy regularly is sweet potato. Baked, boiled, or fried – sweet potatoes are used more often than potatoes in my home, making it a good candidate for the garden. Let's examine what it takes to grow sweet potatoes in our Central Illinois climate.

Sweet potato (Ipomea batatas), is a tender vegetable native to Central and South America that requires a long frost-free growing season to mature. Sweet potatoes are not true potatoes. What is harvested from the sweet potato is a tuberous root as opposed to a white potato which is a tuber.

Early spring is the time to start sweet potatoes from plants called "slips". Order slips from a reputable seed company or make your own. Slips can be started by taking a disease-free, fully grown sweet potato from last year's crop or the supermarket, and bury the bottom three-quarters in moist sand. Soon the root will sprout slips, which are green shoots with exposed roots. Carefully remove the slips and plant them in a cold frame, high tunnel, or in the garden once all danger of frost is clear.

Sweet potatoes should be planted in a mound of loose loamy soil that reaches eight-inches high. Give sweet potatoes plenty of room as these vining plants prefer to spread. At a minimum, space sweet potatoes 12-inches apart and three-feet between rows.

Little care is required once the sweet potato vines establish themselves. Ensure even irrigation; however, don't keep the root zone constantly wet. Do not water during the last four weeks before harvest to protect the developing roots from splitting.

Ideally, wait until after the first frost to harvest sweet potatoes- this concentrates the sugars in the roots. Once frost hits, harvest immediately to keep any decay from spreading aboveground to belowground. If there is a long stretch of cool weather (below 55°F but above freezing) it would be a wise decision to harvest, especially if the plants show cold weather damage. Cure sweet potato roots by allowing them to dry on the ground for two to three hours, and then place in a warm room for 10 to 14 days with a temperature of 85°F and 85% relative humidity. To keep humidity high, wrap individual sweet potatoes in perforated plastic bags or newspaper. Cover the sweet potatoes with a plastic sheet or cloth. After curing, store in a cool (55°F), dry location. Basements work well. Properly cured sweet potatoes should keep the entire winter.

One sweet potato plant will yield at least two pounds. This year I ordered twenty-five slips. Hopefully, my garden hasn't exceeded my appetite once again.