By Matthew R. March, MNRD
Polk County Extension Agent
Sweet potato casserole may steal the spotlight at the Thanksgiving meal, but sweet potatoes are a nutritious vegetable that can be enjoyed year around. Sweet potatoes are an excellent source of vitamin A, with one cup of cooked sweet potatoes providing 768.7% of your recommended daily value of vitamin A. Vitamin A helps the body fight off infection. Sweet potatoes are also a good source of vitamin C which is a powerful antioxidant helping to defend your body against cell damage.
Sweet potatoes are a tropical plant that is well adapted to east Texas due to our warm humid summers. The plant originated from Central America where it is grown as a perennial plant, which means sweet potato vines can live for multiple years.
However, in the U.S. sweet potatoes are treated as a warm season annual crop, meaning the plant completes its entire life cycle in one year. Texas is the fifth-largest producer of sweet potatoes in the U.S. and production is centered around Van Zandt County.
Sweet potatoes are a member of the morning glory or Convolvulaceae family and sweet potato vines resemble ornamental morning glory species known for their vines and colorful flowers. It should be noted Irish potatoes belong to the nightshade or Solanaceae family.
Varieties suited for Texas include beauregard, centennial, jewell and vardaman. Sweet potatoes should be planted on sites that receive full sun. Plants grow best in well drained, fine sandy loam soil with a slightly acidic pH. Soil that remains routinely wet will cause rot and disease issues. Sweet potatoes can handle extremely hot temperatures and can also tolerate light frosts.
However, since the plants thrive best during hot days and warm nights they should be planted well after the last expected frost in the spring and at least 150 days before the first expected frost in the fall. Before planting, incorporate 19 ounces of 15-5-10 fertilizer per 100 square feet. Work the soil into mounds eight inches high and 36 inches wide. Space the mounds 3-4 feet apart.
Sweet potatoes are planted from slips, not from seeds or transplants. Slips are also known as vine cuttings. Slips can be produced at home by buying disease-free sweet potatoes from a local market. Clean and then cut in half. Using toothpicks, suspend each half over a jar of water, submerging half of the piece in water. Place the sweet potato near a window. You will need to change the water regularly. Over the next few weeks, shoots will form on top. When ready to plant, carefully break off the shoots with any attached roots. These are the slips that you will plant.
Maintain even soil moisture throughout the growing season. In general, sweet potatoes require one inch of water per week. Stop watering two to three weeks before harvest. Weed control is very important to allow the vines to cover the soil fully.
The best time to harvest sweet potatoes is immediately before or just after the first fall frost. Sweet potatoes bruise easily so be careful when harvesting and handling. Sweet potatoes can be cured to increase the sweetness of the potatoes harvested. To cure, place unwashed potatoes into a high humidity environment, at a temperature around 85 degrees for two weeks.
While sweet potato casserole may be a popular dish, it is not a very healthy recipe due to all the added sugar. A healthier recipe you may want to try this Thanksgiving is seasoned roasted sweet potatoes.
Seasoned Roasted Sweet Potatoes
—2 pounds (~3 large) sweet potatoes, peeled and cut into half-inch pieces
— 2 tablespoons olive oil
— ¾ teaspoon fine sea salt (kosher salt; use less if using table salt)
— ¼ teaspoon freshly cracked pepper
— ½ teaspoon ground chili powder*
— ½ teaspoon paprika
— ½ teaspoon garlic powder
- Preheat the oven to 425 degrees. Peel and cube the sweet potatoes into half-inch pieces.
- Place cubed sweet potatoes into a large bowl. Add the olive oil, salt, pepper, chili powder, paprika and garlic powder on top.
- Toss to coat all the sweet potatoes. Spread sweet potatoes out on a large sheet pan sprayed with a little bit of olive oil.
- Arrange cubes of sweet potatoes in an even layer. You don’t want any potatoes overlapping or you’ll end up with steamed potatoes instead of roasted potatoes.
- Bake for a total of 27-35 minutes. Flip the sweet potatoes over about every 10-15 minutes.