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Key Points
- Prepare for a long growing season and harvest before the first frost.
- Harvest by digging carefully with a shovel or garden fork.
- Sweet potatoes develop their best flavor after curing and can be stored for up to one year.
Sweet potato plants can each yield eight or more edible roots. These southern staples are sometimes bypassed for more traditional Irish potatoes, but sweets are just as versatile in soups, stews, casseroles, breads, pastries, and desserts. They’re equally delicious baked in the oven and served with a pat of butter.
Sweet potatoes are easy to grow and harvest, retaining flavor and nutrition for up to one year when stored correctly.
Read on to learn more about popular varieties, when and how to harvest these sweet spuds, and tips on storing.
Sweet potato versus yam
In the U.S., sweet potatoes are often called yams, but they are not the same vegetable. Sweet potatoes have a sweeter flavor with smooth skins. Yams are large with bumpy skins, starchy, and more like Irish potatoes. Sweet potatoes are referred to as ‘roots’, while yams are ‘tubers’, usually found only in specialty markets in the U.S.
When to Harvest Sweet Potatoes
Sweet potatoes require warm soil and air temperatures for optimum growth. They need a fairly long growing season of up to 120 days, depending on variety, and should be harvested before the first frost. Yellowing leaves indicate plants are ready to harvest. Here are a few popular cultivars, including some that produce well in northern climates.
- Beauregard: Early, high yields of large roots in 90 days. Dark orange flesh is dense, smooth, and fine-grained with a sweet flavor.
- Jewel: A long-season, lightly sweet variety ready to harvest in 120 days. Yellow-orange flesh is dense and creamy. Stores well.
- Garnet: Medium to large roots ready to harvest in 90 to 110 days. Orange gold flesh is moist and starchy. Cooked leaves are edible with a flavor and texture similar to spinach.
- Vardamon: Compact, bush type for small gardens, raised beds, and containers. Each plant yields three to five pounds of roots with dark orange, smooth flesh in 100 days.
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How to Harvest Sweet Potatoes
Harvest sweet potatoes by digging them with a shovel or fork. If the soil is loose and dry, you can also pull up the primary vines with roots still attached. It’s not necessary to remove excess vines before harvesting; however, cutting them back may save wrestling with long, tangled vines. Follow these steps for an easy harvest without damaging your crop.
- Choose an overcast, dry day for harvesting sweet potatoes. Direct exposure to sunlight can scald tender skin.
- Soil should be lightly moist and loose. Wet soil makes for muddy potatoes and encourages rot. Dry, hard soil makes digging difficult and causes damaged or broken tubers.
- Use a shovel or fork to dig down or loosen soil 6 to 8 inches deep around principle vines starting about 18 inches out from the center.
- Gently lift sweet potatoes from the soil with the shovel or fork. Or you can pull the main vines to lift them out.
- Use your hands to sift the surrounding soil for additional roots.
- Set damaged roots aside for immediate use.
- Sweet potatoes need to cure before storing. Set them out on brown paper in a humid, shady spot for four to ten days.
What to Do About Sweet Potato Vines
Sweet potato vines grow 10 feet long and 6 feet wide on average, with some varieties producing vines up to 20 feet. They often put down roots in increments along the vines, however, these rooted vines do not produce edible potatoes and can reduce yields.
You can either pull the rooted vines up out of the ground or prune them back to just above the next set of leaves.
Gardeners in frost-free climates can start new plants from vine cuttings by removing a section of vine with a leaf node and rooting it in water or soil. Due to the long growing season, vine cuttings are generally not a practical propagation method for northern gardeners.
Leaves are reportedly edible when cooked, with a texture and flavor similar to spinach. Or you can feed the foliage to livestock or add it to the compost pile.
How to Store Sweet Potatoes
Sweet potatoes develop full flavor only after curing and storing for six to eight weeks. Temperatures between 80°F and 90°F with the same levels of humidity, and a location out of direct sunlight are ideal for both curing and storing.
Curing increases sugars and nutrients and toughens skins against accidental damage from handling.
For long-term storage, wrap sweet potatoes individually in newspaper or layer them in a basket or box separated by straw or other dry material. Leave some space between each potato so they don’t touch.
Keep them in a cool, dark location like a root cellar or a dark cupboard at temperatures of 55°F to 60°F for up to a year.
FAQ
Flowering is a natural part of the plant’s energy cycle and is not an indication that roots are ready to harvest. Not all varieties produce flowers. An accurate way to determine if they’re ready is to check your variety for days to maturity and watch for leaves to start yellowing.
Yes. They can develop rot, attract insect pests and rodents, lose flavor and become tough and fibrous. Harvest crops before frost to prevent loss.
