How sweet potatoes grow
By Emmy Ulmschneider and Debbie Roland, Master Gardeners
Sweet potatoes and yams are not the same thing. Yams are herbaceous, perennial vines with a starchy tuber. They are monocots and are in the genus, Dioscorea. They are native to Africa, Asia and Latin America and have spread widely around the world. The tubers can be very large, up to 5 feet with a starchier more potato-like texture, and they are not sweet.
The sweet potato, also a perennial herbaceous vine, is a dicot in the genus, Ipomea as are morning glories. Originating in tropical America, they spread as a food crop reaching North America by the 1700’s. Sweet potato tubers are smaller, generally slender, and with tapered ends. They come in four different colors of skin and flesh. Both yams and sweet potatoes are nutritious but sweet potatoes have more sugar and protein and different vitamins than yams. Yams have more fat, carbohydrates, and fiber.
So, onto growing a sweet potato!
Sweet potatoes are propagated from what is called a slip (a piece or sprout of an actual sweet potato), not a seed. You can purchase slips and in the PBMG Blog Article May 31, 2020), we covered how to make slips. See https://www.westtexasgardening.org/post/growing-sweet-potatoes
It takes four months for a sweet potato to mature but the good news is that they are heat and drought tolerant. They grow in the ground or raised beds and will even grow in sandy soil. So, while your slips are growing, you can prepare your beds:
· Find a sunny spot with well-drained soil. Add compost and coconut coir to build a fertile soil.
· Build raised mounds about 12” tall and about 3’ apart so vines can roam
· Set slips with roots beneath the surface with the stems above ground.
· Water generously for 10 days.
During the summer:
· Keep the weeds out of your beds; don’t use a hoe which could damage the forming roots. Deep water throughout the summer. Don’t prune the vines, they should be growing vigorously.
· Late in the summer reduce your water which will reduce the cracking of the sweet potato’s skin. You will be storing them over winter and cracking can cause spoilage.
Check the tubers and dig up as soon as they are big enough for a meal. Cut away some of the vines and gently, very gently, loosen the soil around the tubers. Shake the dirt off the of the tubers but do not wash them.
Complete your harvest by first freeze and store the tubers in a cool place.
If you have questions, call the AgriLife office in Odessa at 498-4071 or in Midland at 686-4700.
Additional information, and our blog for access to past articles, is available at
westtexasgardening.org. Click on “Resources”.
Perfect sweet potato for beginning slips
Harvest but don't wash if you plan to store.