Sweet potatoes are a warm season plant that should be planted well after any chance for frost, and once soil temperatures are warm. They grow well in our summertime heat and humidity but will need to be picked before the first frost in the fall. In our part of the Carolinas, our first front on average occurs in the first week or two of November. We should plan on harvesting the sweet potatoes by the end of October. Sweet potatoes take 90-120 days to grow to maturity, depending on variety. With a 3 to 4 month growing season, sweet potatoes should be planted by the end of June to make sure they will be ready by the end of October.
A popular variety of sweet potato is Beauregard. It is a very sweet potato with great flavor, light pink skin, and orange flesh. Beauregard is one of the fastest growing varieties at 90-100 days, meaning potatoes planted today will be ready at the beginning of October.
Sweet potatoes are best planted from slips, which are easily grown from last year’s roots. It is difficult to grow slips from grocery store potatoes, because they are usually chemically treated to prevent sprouting during storage. A potato can be encouraged to sprout, then those slips can be rooted, then transferred to the garden.
Sweet potato slips should be planted three inches deep, 8-12 inches apart in rows three feet apart. The vines will grow rapidly and set new roots where they are in contact with the soil. These roots will develop into plump sweet potatoes late in the season.
It is time to harvest sweet potatoes when 30 percent of the roots are greater than 3 ½ inches in diameter. It is important to harvest them before the first frost. Cool soil temperatures will reduce the quality and storage capacity of the potatoes. It is best to cut away all the vines before digging. Take great care to not damage the potato while digging and handling them. They are easily bruised, and the skins can easily be damaged.
After harvesting, the potatoes will need to be cured to convert the starch in the root to sugar. Store the potatoes in the warmest room in your house for two weeks. The temperature for curing needs to stay above 70 degrees.
Once they have been cured store sweet potatoes in a cool location, but not in the refrigerator! Temperatures below 50 degrees will produce off flavors and may rot the potato. Under proper conditions, sweet potatoes will store for up to 6 months.