Sweet Potatoes are a Low-Care, Productive and Tasty Hot Weather Crop
By Dr. Bob Randall
May 2004

Many gardeners dread our five-month summer because the heat and humidity, fire ants and mosquitoes make life outdoors daunting. However, the summer vegetable garden can be one of the most enjoyable gardens of the year because there is a continuous harvest of tomatoes, cukes, green beans, peppers, cantaloupes, and corn. If you planted from February to April you will enjoy this wonderful bounty from now until July. But by August, most of this will be gone, and your enthusiasm for gardening will too. There are many heat and drought resistant tropical vegetables you can plant this month that will produce well with minimal care in late summer. But tops on your planting list should be sweet potatoes because they are healthful, productive, delicious, and need NO maintenance.

 

About Sweet Potatoes

 

If you needed to live off the land in our area, sweet potatoes would be the way. They are a top rated health food with high vitamins, complex carbohydrates (good calories), and fiber. The orange ones also have much more cancer fighting vitamin A (25,000 units per half cup cooked) than other veggies.

 

Obtaining Good Sets

 

Sweet potato varieties differ in how long they take to mature, in the length of vine, in color of skin and flesh, in sugar content, as well as disease and insect resistance. The sweeter ones are known as yams, although they are unrelated to the tropical yam they are named after. There are also low-sugar starchy varieties that are used like Irish potatoes, and there are even varieties grown solely for their delicious cooked greens.

If you have limited space you should grow a “bush” variety with short stems or a quick growing one that will be mature by mid-August, thus freeing up garden space.

Nationwide, about 75% of all commercial sweets are Jewel, but there are better backyard varieties. Jewel is a copper-skinned, orange-fleshed southern potato adapted for sandy, low water conditions.

Beauregard is a productive rose-skinned, deep orange potato that is wilt and rot resistant, but nematode susceptible. It may be the best single variety for our area.

Puerto Rico and Nancy Hall are considered better tasting, but are much less productive. They are adapted to our area, and have short vines. Puerto Rico has copper skin, deep orange flesh and takes 4-5 months to mature. Nancy Hall is the "Yellow Yam" popular in the 1930's. It has light skin, yellow flesh, is juicy, waxy, and sweet when baked. This is a flavor favorite.

Georgia Jet is the fastest producer (2.5 to 3 months). It is deep red skinned with deep orange flesh. Vardaman is a 3-5 month maturity potato with golden skin, deep red-orange flesh, red leaves, and is wilt resistant. It has short vines, is productive, and the potatoes store.

Centennial is clay-tolerant, wilt resistant, stores well, has red-orange skin and deep orange flesh with 20 ft vines.
Gourmet varieties include both Purple (with long vines, deep purple roots and a delicious purple flesh) and the brilliant white-fleshed variety Southern Queen.

Sumor is very productive and produces a large Idaho-potato like tuber that after long storage will almost substitute in potato salad or when baked. Cuban bonaito is similar.

If you have a sweet potato that you like, and it is organic (or has not been injected with growth retardants), you can make your own sets. Put the bottom end of the potato in a narrow container and put in some water. Keep the potato in a warm and bright place at 80-85° until there are four-inch sprouts. Pull these off the potato and stand their ends in clean water while they develop roots. Then plant these sets as described below.

To get some of the best varieties, you will need to buy the sets. Locally, Wabash Antique and Feed sells a selection. The following companies sell sets by mail: Sand Hill Preservation , Victory Seeds, Park Seed, Gurney's, Henry Field's. In summer, we sometimes have cuttings of the tuberless sweet potato spinach at Urban Harvest.

 

Planting Sweets

 

Sweets need a deep, sandy, well-drained soil. In most of our area, the natural soil is clay and unsuitable. But many of us garden in beds with improved soil raised 8 inches or more and 4-5 foot wide. If you do, temporarily convert this bed to a narrower, higher one by digging one spade-width of soil from each side of the bed and toss this into the middle to make a bed, 2-3 ft. wide and a foot high. Flatten the bed, fertilize, plant two rows of slips 9-12 inches apart and water. Then mulch the bed.

 

Growing Sweets

 

You may need to water the young sets for a few days, and possibly in August if they wilt and brown after a long dry period, and you may want to pull a few tall weeds, but generally the sweet potatoes will be fine without care until you get around to digging them in 90-150 days.

 

Harvesting Sweets

 

Sweets continue to enlarge and multiply until the soil temperatures drop in late November. At that time, they must be dug to avoid rotting, but taters dug earlier will have less rotting and less bug problems. I tend to harvest between mid-August and the end of October a few feet of potatoes at a time. These should be washed in a bucket and then cured for a few weeks in paper sacks on top of the refrigerator. To keep them beyond that, they need to be stored at 60° in a bug proof place. At lower temperatures they rot and at higher ones they sprout.

 

Eating Them

 

The great agronomist George Washington Carver said that baking was the best way to cook a sweet potato, but he even had recipes for sweet potato cobbler!