How to Plant Sweet Potatoes in Your Backyard, According to Experts

Sweet potatoes have been a staple crop for millennia, and with good reason. These healthy root vegetables are full of antioxidants and are relatively easy to grow—all you need is some time and a little know-how. To learn more, we asked experts to break down exactly what you need to know to plant, grow, and harvest your own sweet potatoes.

How to Plant Sweet Potatoes 

Sweet potatoes aren’t grown from seeds but from sprouts (known as slips) that come from mature sweet potatoes. "Start by selecting healthy, organic sweet potatoes," says Charmaine Peters, farm director at Arden. "Look for firm ones without any signs of damage or disease."

Consider sourcing a sweet potato from a nearby farm, nursery, or local grocery store. Then follow these instructions to start your best sweet potato crop. 

Step 1: Prep Your Soil

Sweet potatoes like an acidic environment, so you may want to test your soil before planting. They also require good drainage and full sunlight. "You may want to consider planting in raised beds if your soil isn’t ideal, as they allow for better control of soil quality and drainage," Peters says.

Step 2: Propagate Slips

Once you’ve selected a healthy sweet potato to propagate, Peters suggests placing it horizontally in a jar filled with water. Use toothpicks around its middle to suspend the potato so that its bottom half is submerged, then position the jar in a warm location with indirect sunlight. Change the water every few days to keep it fresh. 

Within two to four weeks, slips will emerge from the sweet potato and grow into vines. "Once these reach about 6 to 8 inches in length, carefully twist them off the sweet potato," Peters says. "Each slip should have a small cluster of roots at its base."

Step 3: Plant Slips

Sweet potatoes grow best when they are spaced 12 to 18 inches apart. Mariah Henry, director of urban agriculture at Carolina Farm Trust, suggests the following steps for planting:

1. Dig a hole 4 to 6 inches deep. 
2. Place one slip in the hole with the leaves above ground. 
3. Fill in the hole with soil, making sure all the roots are fully covered. 
4. Continue with all remaining slips. 
5. Give each plant a healthy drink of water after transplanting. 

Step 4: Hill Your Crop

When your plant reaches about 6 inches tall, Henry recommends "hilling" the potatoes. "Soil is gathered and piled on top of the base of the sweet potato plant," she says. "This process encourages tuber growth, which produces potatoes."

Keep the slips well irrigated to promote growth and production, and adjust the watering frequency as needed. 

Caring for Sweet Potatoes

While sweet potatoes are considered a relatively easy crop, they require a few specific conditions in order to thrive.

Sunlight

Sweet potatoes require at least six to eight hours of direct sunlight per day. "If you grow sweet potatoes in partial shade, their growth can slow down, and their leaves may fade or look less vibrant," says Peters. 

Temperature

Sweet potato slips should be planted outside about two to four weeks after your last frost date has passed, says Luay Ghafari, creator and recipe developer at Urban Farm and Kitchen. "But a more important indicator is soil temperature," he says. "The soil temperature should be at least 65 degrees Fahrenheit, and I recommend using a soil thermometer."

Warm soil helps sweet potatoes grow quickly and develop strong, healthy roots. They are sensitive to frost, so provide protection if temperatures drop below 50 degrees. 

Soil

Peters encourages planting sweet potatoes in well-draining sandy or loamy soil.  "Avoid using poorly drained, heavy, clay soil because it can make your sweet potatoes smaller, longer, or misshapen," she says. "Heavy soils can retain too much moisture, leading to root rot and other fungal diseases."

Fertilizer

Once the soil reaches the optimal temperature, Ghafari recommends a high phosphorus amendment. "Phosphate helps promote root growth, which is exactly what we want as sweet potatoes grow underground," he says. "Throughout the season, sweet potato vines can be fertilized with a liquid fertilizer higher in phosphate and potassium than nitrogen. If you use a high-nitrogen fertilizer, it’ll promote the growth of green foliage, not roots."

Sweet Potato Varieties

The most popular sweet potato varieties in the United States include Beauregard, jewel, and garnet, according to Peters.

• Beauregard is known for its reliable yields and adaptability to different growing conditions. "My favorite is Beauregard," says Peters, "because they’re the easiest variety to find in supermarkets, and they can reliably produce large, delicious tubers with minimal effort in my garden."
• Jewel also produces high yields and is renowned for disease resistance.
• Garnet usually grows consistent in size and shape, so they often have more appeal for culinary uses.
• Luminance features bright purple skin and a creamy white interior.
• Purple Majesty has a dull purple exterior and deep purple interior.
• Georgia Jet is a red-skinned variety that matures in 90 days, which Ghafari says is perfect for northern gardeners. 

"When choosing which varieties to grow at home, it is critical to understand the days to maturity," Ghafari says. "Some sweet potatoes will be ready to harvest within 100 days, and others may need up to 120 days or more. The length of your season should help determine the varieties you choose to grow in your home garden."

Common Pests and Diseases 

Various diseases can infect sweet potatoes, including soft rot and black rot. Some fungi that cause storage rots can infect roots in the field or enter through wounds during harvest or handling. 

In addition, pests like weevils, whiteflies, and root-knot nematodes are also common problems in sweet potato farming. "Weevils lay eggs on vines and bore into tubers, causing damage," she says. "Whiteflies sap leaves, weakening plants, and spreading viruses. Nematodes form galls on the roots. These are abnormal growths or swellings, disrupting nutrient and water uptake, resulting in stunted growth and lower yields." 

Harvesting Sweet Potatoes 

Sweet potatoes are ready for harvest when the vines turn yellow and begin to die back—usually in late summer or early fall, about three to four months after planting. Gently dig around the base of the plant if you’re unsure whether your tubers are ready for harvest.

When ready, follow these steps for harvesting:

1. Cut off the vines a few days before to toughen up the skin. Reduce irrigation to let the soil dry out. 
2. On the day of harvest, lightly water the soil to soften it and reduce damage to the potatoes. 
3. Use a garden fork or shovel to carefully lift the soil around the bed edges to avoid damaging the potatoes during extraction. 
4. Gently lift the plant from the soil and allow excess soil to fall off.

Once harvested, Peters stresses the importance of avoiding bruising, scraping, dropping, and washing the sweet potatoes. Otherwise, they won’t store well. "The benefit of growing sweet potatoes at home is that you don’t need to pull them all at once. Harvest what you need," Ghafari says. "However, make sure to harvest the entire crop before the first frost."

Curing and Storing Sweet Potatoes

Freshly harvested sweet potatoes can be used right away, but Ghafari recommends curing for long-term storage. "Curing sweet potatoes allows them to form a tougher skin, which makes them keep for longer," he says. "It also gives them a sweeter taste."

Cure harvested sweet potatoes by placing them in a warm place, such as a covered porch, shed, or garage, for 10 to 14 days. Lay them out on a flat surface so that they don’t touch. "You can wrap them in newspaper to absorb excess moisture and prevent them from touching each other, which reduces the risk of rot and extends their freshness," says Peters. "Do not refrigerate them, as the cold can affect their taste and texture. Also, check them regularly for spoilage and remove any that are soft, shriveled, or sprouting to keep the rest fresh for months."

Sweet potatoes should last several months if stored in a cool space, roughly 50 to 60 degrees Fahrenheit.