The tuberous roots should be harvested by the time frost kills the vines or soon thereafter. Sweet potato roots continue to grow until frost kills the vines. Roots can be left in the ground for a short while; however, a hard frost can cause damage to roots near the surface.
Winter storage is the same for eating sweet potatoes and slip-producers. It's best to keep them inside somewhere, in a dark place, like in boxes or paper bags in a closet, and then covered with a blanket to keep out any sunlight. The ideal storing temperature is between 55-60 degrees.
Will sweet potatoes come back next year? They can live through the winter in USDA hardiness zones 9 to 11. So, if the roots survive the winter, they'll regrow. But if you live in a zone colder than 9, you'll need to either give them significant protection over the winter or plan to replant them every year.
Proper Storage
Ideal storage conditions include an ambient temperature of 55-60°F and relative humidity of 85-90%. Under these conditions, sweet potatoes remain viable for several months. A cellar, basement, or an outdoor storage house (when temperatures are cool) would be ideal.
Store sweet potatoes in a warm building where the air is dry and the temperature uniform. The curing room may also be the storage room if conditions are right. Temperature during storage should be kept as close to 55 degrees F.
Sweet potato roots continue to grow until frost kills the vines. Roots can be left in the ground for a short while; however, a hard frost can cause damage to roots near the surface. Chilling injury also results to roots when soil temperatures drop to 50°F or lower, and this can result in internal decay in storage.
If you are storing raw sweet potatoes, make sure you do not rinse them first. Rinsing could lead to rotting due to the extra moisture that is being introduced. Use a dry cloth to remove any dirt before you begin to store sweet potatoes. Another way to store raw sweet potatoes is to cure them for 1 to 2 weeks.
To overwinter the tubers, cut the vines to ground level, then dig them up before the first frost in autumn. Dig carefully and be careful not to slice into the tubers. Brush the soil lightly off the tubers, then store them, not touching, in a cardboard box filled with peat moss, sand, or vermiculite.
Ornamental sweet potato vines will come back every year if you live in a warm enough climate (zones 9+). However, they will not survive outside through the winter in colder climates.
Store sweet potatoes loose (not in a plastic bag) in a cool dark well-ventilated place; avoid keeping sweet potatoes in the refrigerator. The skin can be left on (scrub well) or peeled. Slice, dice or bake whole, just like potatoes. Sauté, barbecue, fry or microwave.
Generally speaking, storing potatoes in the ground is not the most recommended method, especially for any long term storage. Leaving the tubers in the ground under a heavy layer of dirt that may eventually become wet will most certainly create conditions that will either rot the potato or encourage sprouting.
If you don't harvest potatoes when the plant dies back, a couple things could happen. Most likely they will rot if the soil is wet, or they'll die once the ground freezes. But if you live in a warm and dry enough climate, any tubers that survive over the winter will sprout again in the spring.
Do potatoes keep growing after the plant dies? Once the plant dies, the potatoes are finished growing in size. However, the skin on the potato does harden and cure to make it stronger for storage. We recommend leaving the potatoes in the ground for about 2 weeks after the plants have died off.
Most plants can survive a temperature as cold as 1 degree Celsius, or just under. Sweet potatoes, however, are more vulnerable. If they get down to about 4 degrees Celsius—the temperature of a refrigerator—they'll suffer a chilling injury that will damage the whole plant.
After harvest, the sweet potatoes should be cured. This involves placing the potatoes in a warm (85 degrees) humid (90 percent) environment for about 4 to 6 days to increase sugar content, heal nicks and bruises incurred during harvest, and increase flesh color.
For long-term storage, place the potatoes in a cool, dry, and dark area where temperatures won't fall below freezing or rise above 60 degrees. They'll keep best between temperatures of 35 and 40 degrees.
The long vines of sweet potatoes can overrun a garden. In early to mid-September, feel free to cut them back by 25%. This simply makes the plants easier to deal with when digging. Sweet potatoes with edible tubers developing below the ground.
Once rooted, they can be moved to their permanent container, placed in a sunny location and watered as needed. You can also take cuttings of your sweet potato vine and grow it like a houseplant for winter. Or store the tuberous roots in a cool dark location.
Or, you can start your own (see how below). Before ordering slips, make sure that you have a long enough growing season to actually grow sweet potatoes. Most varieties will take about 90 to 120 days to mature. See your frost dates and length of growing season.
The answer is yes and no. Potatoes (Solanum tuberosum) are perennial plants and some cultivated potatoes can be quite hardy. The ability of cultivated forms to survive winter cold depends on the variety (there are over 4,000 known types), but most will not withstand hard freezes.
Sweet potatoes love the heat of summer and do not tolerate any frost. The warmer, the better the harvest will be. In our area, heat-loving plants will need help. If you have a greenhouse, you can grow the sweet potatoes in there.
While it's tempting to eat your newly harvested sweet potatoes immediately, it's important to let them cure first. During the curing process, the starches inside the sweet potatoes convert to sugars, and that takes about two to three weeks with proper storage.
Wait to wash your sweet potatoes until you are ready to use them. The moisture could cause them to rot and lead to mold. If you'd like, use a dry cloth to brush off any dirt before storing, especially if it will dirty up your shelf or cabinet.
Sweet potato skins are safe to eat and can be easily added to most recipes. They're rich in fiber, other nutrients, and antioxidants that can help support a healthy gut, increase feelings of fullness, and prevent chronic disease. If you're looking to get the most nutrition out of your sweet potato, keep the peel on.
Can you freeze raw sweet potatoes? It's not recommended to freeze raw sweet potato fries or cubes. They won't hold up well in the freezer and they won't cook correctly in recipes. Blanching or cooking sweet potatoes fully is the way to go.