The first step in learning how to grow sweet potatoes is discovering that they are not related to regular potatoes and are not developed the same way. Unlike regular potatoes, you can't just plant a whole sweet potato in the ground and expect a crop; it will rot underground. Sweet potatoes are grown from sweet potato slips. Slips are the stems and foliage that sprout from already grown sweet potatoes. Twist them off the potato, root them in water, then plant them. In three to four months, you should have some sweet potatoes.
Sweet potatoes are always planted in the spring. They are slow-growing and require warm temperatures to develop full-size tubers. You can usually get three to five tubers per plant and more if you're in a warmer climate. Sweet potato plants come back every year if you live in a warmer growing zone (USDA zones 8 through 11). The orange-fleshed sweet potatoes are the most familiar, but sweet potatoes can be white, yellow, and even purple. If you have a smaller garden, you can grow bush varieties.
Learn How to Grow Sweet Potatoes
|Common Name||Sweet potato|
|Botanical Name||Ipomoea batatas|
|Plant Type||Herbaceous perennial, usually grown as an annual vegetable|
|Mature Size||Vines spread to 20 ft.; tubers average 4-6 in.|
|Sun Exposure||Full sun to part shade|
|Soil Type||Medium-moisture, well-drained soil|
|Soil pH||Acidic (5 to 6.5)|
|Bloom Time||3-4 months after planting|
|Hardiness Zones||8-11 (USDA)|
|Native Areas||North America, South America|
What are the Differences Between Yams and Sweet Potatoes?
How to Plant Sweet Potatoes
When to Plant
These plants are tropical in origin, so wait until the soil has warmed up fully before planting.
To give them a head start, sweet potatoes are often planted in raised rows, about 8 inches high. This helps the soil warm faster and keeps them well-drained. If you are gardening in a cooler climate, spreading black plastic on the soil will also help it warm faster.
Selecting a Planting Site
Sweet potatoes will generally thrive in any average well-drained soil in a sunny location. If your soil is too dense or rocky, consider planting sweet potatoes in raised beds filled with sandy but rich potting soil.
Spacing, Depth, and Support
Plant slips about 12 to 18 inches apart with 3 to 4 feet between rows. The vines will spread and fill in, so give them plenty of room.
Sweet Potato Care
Be sure to plant your sweet potatoes in full sun to part shade. They generally prefer full sun but appreciate some afternoon shade in hot, dry regions.
Sweet potatoes prefer soil that is well-drained but high in organic matter. Sandier soil is preferable to dense, clay soil.
Once established, sweet potatoes will tolerate growing in dry soil. It's best to keep it evenly moist with 1 inch of water given once a week. Don't water your sweet potatoes during the final three to four weeks prior to harvest to prevent the mature tubers from splitting. Keep the plants moist, especially during dry spells.
Temperature and Humidity
Sweet potatoes should not be planted outdoors until the temperature of the soil has warmed to 60 degrees Fahrenheit. They need soil growing temperatures between 60 to 85 degrees Fahrenheit and an air growing temperature of 65 to 95 degrees Fahrenheit. Choose short-season varieties if you live in the northern part of the country.
Sweet potatoes are not heavy feeders, but it's important to give them balanced nutrition, typically with proper soil preparation. Overfeeding tends to promote growth of foliage rather than tubers. The best approach is to add compost to the beds before planting the sweet potatoes. Alternatively, you can apply an organic liquid fertilizer to the soil prior to planting.
Types of Sweet Potatoes
- 'Beauregard': This popular commercial variety produces a potato with pale reddish skin and dark orange flesh that takes 100 days until it reaches maturity.
- 'Bush Porto Rico': This compact vine yields a potato with copper skin and orange flesh after 110 days. This variety has big yields, so it's a good choice for smaller gardens.
- 'Centennial': This cultivar offers good disease resistance and is relatively quick to mature, averaging about 90 days to maturity.
- 'Georgia Jet': Another fast-maturing variety, 'Georgia Jet' is prized for its reddish skin and orange flesh; it matures in about 90 days.
- 'Patriot': Outstanding pest resistance makes this variety a popular choice for organic gardens. The potatoes have copper skin and orange flesh.
Sweet Potatoes vs. Sweet Potato Vines
Sweet potatoes may be associated with growing only in the southern United States, but they will actually grow in just about any garden anywhere. The part we eat is the tuberous root of this warm-weather perennial vining plant. Edible sweet potatoes are closely related to morning glories (Ipomoea tricolor) and are the same species as the sweet potato vining plants commonly grown as ornamentals. The edible and ornamental types are different cultivars of Ipomoea batatas.
Harvesting Sweet Potatoes
Three to four months after planting, the tubers should be ready to harvest for eating, depending on the cultivar. If you like to eat the leaves as greens, you can do so in moderation throughout the season. Be sure to leave enough leaves to keep the plant growing.
You can dig up your tubers once the foliage starts to yellow. If the foliage is hit by a frost, the tubers are probably still fine. Just don’t let them sit in the ground too long after the tops die back or they could start to rot. Be gentle when digging. Sweet potato tubers grow close to the surface. Their skins are tender and can be damaged and bruised easily.
How to Grow Sweet Potatoes in Containers
If you want to experiment with growing edible sweet potatoes, try starting them off in containers. Sweet potatoes are easy to grow in containers. Start small plants you purchase in the spring or grow slips in pots. Loosely fill a large container of any material with lots of drainage holes with high-quality potting soil. Make a hole large enough to cover the roots of your plant or slip. Water it thoroughly, and put the pot in a sunny spot. Move the pot outdoors once the threat of frost has passed.
You can try to grow sweet potatoes indoors, but it is challenging. The yield is often small after a four-month wait. They require a lot of sun, heat, and water, which is harder to replicate indoors.
Sweet potato vines will grow in a rambling fashion, but they should not be trimmed because they are important to help feed the potatoes. If your vines are wandering out of control, use your hands to turn the vines back toward the garden.
Propagating Sweet Potatoes
Propagate sweet potatoes with slips or by saving tubers for replanting. If you put a sweet potato in water, you won't get more potatoes, but it will develop slips that you can plant that will develop sweet potatoes. If your winters are longer than a couple of months, you can propagate sweet potatoes by saving tubers over the winter and planting them the following spring. If you live in an area with short winters, you can begin new slips from vine cuttings or whole potatoes.
Propagate with saved tubers using these steps:
- Use a shovel to carefully dig up the tubers before the first frost in the fall. Gently brush the soil off the tubers to prepare them for storage.
- Store them over the winter in a sturdy cardboard box filled with peat, vermiculite, sand, or other dry material. Make sure the tubers are not touching each other in the box.
- Keep the box in a cool, dry place without light (such as a basement or root cellar). Make sure the tubers in the box won't freeze. Place a blanket over the box to ensure warmth.
- In spring, the tubers will start to sprout. Divide them into pieces, making sure that each piece has at least one eye.
- Plant them in the garden after the threat of frost has passed and the soil temperature is at least 60 degrees Fahrenheit.
Propagate by creating slips from vines using these steps:
- Use a sterile, sharp cutting tool to snip off about 6 inches from the tips of healthy vines, before the first frost.
- Place the cuttings in a jar with room temperature water.
- Once they develop roots, plant them in pots filled with good-quality potting soil.
- Keep them in a sunny location until it’s time to plant them outdoors.
Propagate by creating slips from full-grown whole sweet potatoes using these steps:
- Use a sterile, sharp knife to cut a full sweet potato in half lengthwise.
- Place each half on a bed of damp potting soil using a deep tray.
- Cover the pieces with a few inches of soil.
- Keep the pieces moist and warm.
- Small roots should develop within a few days, followed by leaves.
- They are ready to be lifted and planted in containers once they’re between 4 and 8 inches tall (about six weeks). Keep them in a sunny location until it's time to plant them outdoors or in larger containers.
Overwintering sweet potatoes is the same as propagating them for the next growing season. Before the first fall frost, cut the vines to the ground. Carefully dig up tubers with a shovel and gently brush the soil from the tubers. Then store them in a box filled with dry material, make sure the tubers are not touching, and place the box in a cool, dry place where the tubers won't freeze. Cover the box with a blanket to make sure no light reaches the tubers.
Common Pests and Plant Diseases
Wireworms and root-knot nematodes are the biggest problems when growing sweet potatoes in home gardens. Damage is lessened if you rotate your crop each year. Many diseases can be avoided by choosing disease-resistant varieties and using certified disease-free sweet potato slips. Mice can also be a problem, so be on the lookout.
Are sweet potatoes easy to grow?
Sweet potatoes are surprisingly easy to grow. Since the vines root wherever they touch the ground, a few plants can easily produce a generous harvest.
Can you plant sweet potatoes indoors?
Growing edible sweet potatoes requires warm weather and a large container with a lot of drainage holes; In other words, it can become quite messy to grow sweet potatoes indoors. Sweet potato plants also tend to become root bound in smaller pots, so it's best to grow them outdoors in bigger containers or in the ground.
Can I plant a garden of sweet potatoes with varieties from the grocery store?
Sweet potatoes grown for consumption are usually planted from purchased slips—small rooted pieces of a tuber—or from tubers that you can root at home. You can try growing sweet potatoes from the grocery store, but the only way to be certain you have certified disease-free roots is to buy slips from a reputable seed supplier.
Sweet Potato Production and Pest Management in Georgia. University of Georgia Extension.