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Can you dig it?

It's time to harvest sweet potatoes.


Linda Geist
University of Missouri Extension
Phone: 573-882-9185

Published: Wednesday, Oct. 19, 2016

Story source:

David H. Trinklein, 573-882-9631

Your Show-Me Garden: MU Extension brings you gardening tips from experts around the state.

COLUMBIA, Mo. – The first frost of fall is fast approaching, which means it’s time to think about harvesting your sweet potatoes.

The warm-season root vegetable does not tolerate cold weather, says University of Missouri Extension horticulturist David Trinklein. Table quality of sweet potato slides when harvested after temperatures drop below 50 degrees.

Dig up sweet potatoes after the first light frost for best results, Trinklein says. Dig the thin-skinned sweet potato carefully to avoid bruising. Gently lift the roots from the soil with a potato fork. Remove soil from the dug potatoes and let them dry on top of the soil in the sun for a few hours.

Separate cut sweet potatoes from undamaged ones. Cut potatoes ooze a milky liquid. The cut areas need time and space to heal.

Cure sweet potatoes in a warm (80-85 degrees), humid area for about 10 days. A loose plastic cover over the potatoes creates the desired high relative humidity. Curing produces a higher sugar content and improves the color. It also allows minor wounds to heal. Uncured potatoes lose quality.

Store above freezing temperatures in a basement or unheated garage. Ideal storage temperature is around 55-60 degrees. Sweet potatoes can be stored six to 10 months. Do not refrigerate.

Sweet potato is thought to be native to tropical South America, said Trinklein. Incas and Mayans grew sweet potatoes for food more than 5,000 years ago. Columbus likely encountered the sweet potato in early voyages to the West Indies, but did not record it until his fourth voyage. He is credited with introducing the sweet potato to Europe around 1500.

Sweet potatoes need a long growing season, maturing in about 100-110 days. They grow best during long, hot summers.

The spud is no dud when it comes to versatility, flavor and nutrition, said Trinklein. Sweet potato is perhaps the only vegetable with dual roles as main course and dessert. Ornamental sweet potato plants fill flower planters with their distinctive chartreuse and deep purple foliage.

Sweet potato probably deserves more attention in the diet of the average American than it gets, said Trinklein. It is rich in starches and complex carbohydrates for energy, and it contains significant amounts of dietary fiber, beta carotene, and vitamins C and B-6. It is an important source of minerals such as calcium, magnesium and potassium. It also is relatively low in calories; a 100-gram serving is estimated to contain about 115 calories.

Fun facts about sweet potatoes:

-Sweet potato is a member of the morning glory, or Convolvulaceae, family.

-Sweet potato was grown in what is now Virginia as early as 1648. Even today, sweet potato is more popular with southerners than northerners.

-North Carolina raises the most sweet potatoes in the United States, according to the U.S. Department of Agriculture.

-Missouri native and agricultural scientist George Washington Carver is credited with developing more than 125 sweet potato products, including dyes, wood fillers, candies, pastes, breakfast foods, starches, flours and molasses.

-Yam and sweet potato are often confused with each other. Despite a physical similarity, they are not closely related. True yams are not grown in the United States. Orange, moist-fleshed sweet potatoes are often labeled “yams” in the U.S. to distinguish them from the pale, dry-fleshed types.

For more information:

-“October: Sweet Potato Harvest Time,” Missouri Environment and Garden newsletter,

-“Growing Sweet Potatoes in Missouri,” MU Extension publication G6368,