How to grow and cook sweet potatoes

A gardener and a chef team up with advice on growing and serving sweet potatoes, including a recipe for a delicious sweet potato cake.

Courtesy of Anne K. Moore
Sweet potatoes, which are harvested in the fall, need a long, hot growing season.
Courtesy of Linda Weiss
This sweet potato cake is moist and delicious. Instead of being flavored with cinnamon and similar spices, as is traditional, it includes two different tastes of lemon.

When a reader left a comment wondering when we would be doing something sweet, Linda and I were ready with the sweetest Southern fall crop, sweet potatoes.

You grow sweet potatoes (Ipomoea batatas) from rooted cuttings, called slips, planted into warm garden soil (May in South Carolina, where we live). Their growing requires 90 to 150 days to mature, depending on type.

These tropical vegetables love the heat and humidity of Southern summers, but must come out of the ground before any frost hits the garden. When the vines turn yellow, it is time to dig. If frost is forecast, dig them even if the plants are still green. Even a light frost will travel down the stem and damage the swollen roots we know as sweet potatoes.

Harvesting and curing

Cut the vines, then carefully dig the roots, which bruise quite easily, with a spading fork, gently lifting the soil from deep underneath the plants.

The next activity will be to get them to “sweeten.” Sweet potatoes come out of the ground starchy. They need high heat and humidity to reach their full sweet potential. The longer you can store them at 85 degrees F. and 90 per cent humidity (up to two weeks), the sweeter they will become. If summer has turned to late fall before your harvest, try curing the sweet potatoes in the kitchen, usually the warmest and most humid room in the house.

Once the sweet potatoes are dried and cured, they can be stored at warm temperatures, anything above 50 degrees F. Six to eight weeks of storage will improve their sugar content and sweetness.

Colder storage will harden the core of the sweet potato and ruin the taste. Never, ever put raw sweet potatoes into the refrigerator. Cook them first. To keep them for any length of time, wash them, boil or bake them, then after draining, package them with their skins intact and freeze or refrigerate them.

You won’t have to worry about storage if you try Linda’s …

Unusual sweet potato cake

A lemon-flavored sweet potato pone that my (Linda's) father loved, inspired this very moist and sweet cake with a touch of lemon flavoring. The sweet potato pone was made by an elderly woman who knew and cooked by the old "foodways" (that is, cooking the old way, preserving the past) at a little cafe in southwest Alabama. Her name has slipped my mind over the years, but the thought of her luscious sweet potatoes has not.

This cake [see second photo above; click on the arrow at the right base of the first photo] has no cinnamon, no spices, but is very moist and delicious with a nice contrast in flavors from the lemon extract and the lemon-flavored yogurt.

I like my cake sweet, and this is, sweet and Southern, just as you would expect from a sweet potato cake.

Sweet Potato Cake With Lemon Glaze

3 sticks softened butter

3 cups sugar

2 cups packed mashed sweet potatoes (see note)

6 eggs (at room temperature)

1 teaspoon lemon extract

1 (6-ounce) container lemon-flavored yogurt

3 cups all-purpose flour

1 teaspoon salt

1/2 teaspoon baking soda

Preheat oven to 325 degrees F.

Prepare a large tube pan by spraying with baking spray.

In a large mixing bowl of an electric mixer with paddle attachment, add the butter and sugar. Beat until creamy.

Add the eggs one at a time and mix well. Add the mashed sweet potatoes, and mix well on low speed. Add lemon extract. Mix the salt and baking soda into the flour. Alternate adding the flour mixture and the yogurt to the batter. Turn the mixer on medium high and beat for 1 minute.

Pour the cake batter into the prepared pan. Bake for approximately 65 minutes, or until a cake tester comes out clean. Place on a wire rack to cool for 20 minutes. Turn out onto a heat-proof serving plate. (I like to turn the cake back over to the top side). Let cool before slicing. Serves 8 to 10.

Note: I used 3 medium baked sweet potatoes to make 2 cups mashed. Make sure they are completely done -- the potatoes will be very soft and you can squeeze them.

Lemon Glaze

1 cup confectioners' sugar

1/3 cup lemon juice

Mix together and drizzle over the cake.

Editor's Note: To read more of Anne and Linda's "how to grow and prepare" series, click here.


Linda Weiss and Anne Moore met while Linda was the food editor and Anne was the garden editor for South Carolina Homes & Gardens magazine. They now write articles for the ETV GardenSMART television show website, where Anne is the horticulture editor, gardening consultant, and e-newsletter editor. Anne has written for magazines and newspapers. She is a member of and a recipient of a Silver Award for magazine writing from the Garden Writers Association. Linda is a personal chef. She attended Le Cordon Bleu of Paris’ catering program, has appeared as a guest chef on numerous television shows, has been a culinary educator for 10 years, and a food writer for a number of magazines. She is a professional member of The James Beard Foundation and the Southern Foodways Alliance. She has written a cookbook, "Memories From Home, Cooking with Family and Friends."

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