Sweet potatoes were originally domesticated in Central or South America between five and eight thousand years ago. What a gift this calorie and nutrient rich food must have been when it was first discovered! Today the world enjoys a multitude of colors, textures and flavors of sweet potato, all originating from those first fore-potatoes. As selections were made for appearance and taste, selections for growth habit and season length also occurred. Now sweet potatoes may be grown successfully wherever vegetables are grown.

Starter Plants

Growing a crop of sweet potatoes begins with the slip, or starter plant. The slip is merely a rooted cutting of a sweet potato plant, which was sprouted from the tuber. Slips may be purchased, or you can make your own using a smallish seed sweet potato. It is possible in areas with longer growing seasons to plant a piece of the seed potato itself, like we do with the other potatoes, but most of us would not be able to grow the crop to maturity by doing so.
A couple of months before planting time, select your seed potato (one thatís nice and firm and about two-inches in diameter). Push four toothpicks into the sides so that the potato may be held vertically in a glass of water with the bottom slightly suspended, the toothpicks resting on the rim of the glass. Put just enough water in the glass to cover the bottom of the sweet potato; maintain this water level and change the water every few days. Place the seed potato glass into a sunny window. The sprouts that form will leaf out and can be broken off the parent plant and planted individually when roots begin to form.

Growing Season

Growing sweet potatoes requires an average of around one hundred days in warm, well-drained soil of average fertility. Gardeners in cooler climates may find it beneficial to pre warm the soil by covering the sweet potato bed with black plastic for a few weeks prior to planting. Varietal selection is important for success as well, with some varieties requiring only 90 days or so to mature and others up to 125 days. In areas with short summers, pay close attention to the number of days to maturity.
Prepare the bed by amending the soil liberally with organic compost. Hilling the soil six inches or so will benefit growers with heavy soil. Doing so can also help warm the soil more quickly. Plant the slips deeply (six inches or so), leaving only the top leaves above the soil. Plants should be spaced twelve inches apart in rows three and a half feet apart. Water them well. Sweet potatoes are very drought tolerant once established, but providing an inch of water per week will ensure good root development. Mulching after planting, if black plastic is not already employed, helps conserve soil moisture and keeps the soil in a loose state that promotes root expansion.


It is possible to wait the recommended number of days to maturity, then harvest the roots. I have done this in Georgia to make space for a fall crop, planting a short season variety in May and harvesting in August.
Harvesting during hot weather can be helpful for the curing process as well. However, if having the biggest possible harvest is the plan, let them grow until the vines turn yellow in fall. Be careful not to expose sweet potatoes to anything colder than a light frost as freezing temperatures can damage the crop. To harvest, remove the vines first. This will allow access to the roots without getting your feet tangled up. Dig the roots with a spade fork, starting at the outer edge of the patch and working toward the center. The largest potatoes grow where the slips were planted, but smaller sweet potatoes form where the vines spread across the ground and root themselves in. The longer they are in the garden, the more and larger these secondary tubers grow.

Curing and Storing

Curing sweet potatoes after harvest heals scars on the skins, improves storage quality, and develops the fullest flavor. To cure the crop, they must be held in warm, humid conditions for up to two weeks before moving to long term cool storage. The curing location must be dark, have good air circulation, humidity of around 90%, and a steady temperature of around 85 degrees. If conditions are perfect and consistent they may be cured in a week. I have kept them on my carport in covered milk crates to cure for over a month in late summer with very good results.
Store the crop in a cool, humid environment. The ideal conditions are 55 to 60 degrees with 85- 90% humidity. Condensation is bad for storage, so good air circulation and consistent temperature are very important. My unheated basement works perfectly. Sweet potatoes, will keep well in these conditions for six months or more.
If you intend to use your crop for seed potatoes, there is no need to keep the biggest roots for that purpose. Go ahead and eat the huge family sized sweet potatoes and save the modestly sized ones for seed. Near the end of the storage season it will be time to start slips again.