Freshly dug sweet potatoes may look like the tubers you buy in the grocery store, but they won’t last long or taste their best without curing. Curing or drying sweet potatoes for a few days after harvesting makes tubers last longer and prompts plant starches to convert into sugar, which gives sweet potatoes their characteristically sweet taste. This step-by-step guide explains how to cure sweet potatoes, and provides storage tips to keep the tubers fresh through winter.
Sweet Potato Harvesting Tips
Harvesting sweet potatoes is just the first step. To ensure that your sweet potatoes last as long as possible, follow these tips to avoid common harvesting mistakes.
- Time the harvest. Sweet potatoes are sensitive to the cold and can become bitter and mushy if exposed to hard frost or chilly soil temperatures. For best results, harvest the tubers when the vines begin to die and before soil temperatures fall below 55°F.
- Reduce watering. Excessive watering at the end of the season can cause tubers to crack, which shortens their storage life. To avoid this, reduce watering three to four weeks before you intend to harvest your sweet potato crop.
- Cut the vines. Snipping off sweet potato vines a few days before harvesting doesn’t extend the shelf life of tubers or thicken their skins, but it makes digging them much easier.
- Dig wide. To avoid cutting into the sweet potatoes, use a gardening fork or shovel to gently loosen the soil in an 18-inch-wide circle around the crown of the plants. Once the soil is loose, it should be relatively easy to lift the tubers free from the soil without damaging them.
- Be gentle. Sweet potato skins are delicate and prone to bruising, and it’s easy to pierce tubers with gardening forks or shovels when harvesting them. Always take your time when digging sweet potatoes, and handle the harvest with care.
- Avoid sun. Too much bright light can cause freshly harvested sweet potatoes to develop sunscald. To prevent this, place the tubers in a shady spot after harvesting them, or keep your harvest basket covered with a piece of cloth.
How to Cure Sweet Potatoes
Whether you intend to store sweet potatoes in a root cellar or use them right away, curing the tubers is a good idea. Freshly harvested sweet potatoes have a bland and starchy taste, but curing improves their flavor and reduces the chances of rot by giving minor cuts and abrasions time to heal. Best of all, curing is a quick and easy process you can complete in just a few days.
Step 1: Remove Soil
Sweet potatoes are dirty after they are harvested, but washing them with water can speed up decay. Instead, clean the tubers by gently brushing the soil off their skins with your fingers or a soft, dry brush. If you allow the tubers to dry for a day or two after harvesting them, the dried soil is even easier to wipe away.
Step 2: Inspect the Tubers
While cleaning the sweet potatoes, check for major signs of damage, such as wormholes, large cuts, lots of bruising, or mushy spots. While minor imperfections and small cuts on sweet potato skins usually don’t cause problems, significant damage can speed up decay and cause sweet potatoes to spoil in storage. If you find any damaged sweet potatoes, use them right away because they won’t last.
Step 3: Cure Your Harvest
After you pick out any damaged tubers, spread the rest of the sweet potatoes in a single layer on screens or in slotted baskets and allow the tubers to cure or dry in a protected spot for seven to 10 days. Weather permitting, sweet potatoes can be cured in a shady section of your garden, but you can also cure them under a covered porch or in a potting shed, basement, or garage. It is important to keep sweet potatoes dry and out of direct light while curing, and the curing environment should have high humidity, good airflow, and temperatures ranging between 80°F and 85°F.
Sweet potatoes can also be cured at cooler temperatures ranging between 70°F and 75 °F, but it takes about two to three weeks for them to cure properly. If you need to boost humidity while curing, add a humidifier or keep the tubers covered with a lightweight sheet or cloth.
How to Store Sweet Potatoes
After curing the sweet potatoes, place them in well-ventilated boxes, bins, or crates and store them in a cool, dark spot with good airflow and high humidity. A refrigerator is too chilly for sweet potatoes, but a cool pantry or root cellar that stays around 55°F to 60°F should keep them fresh through the winter. When properly cured and stored, sweet potatoes can last in a root cellar for six to nine months.