How to Cure Sweet Potatoes for Long-Term Storage
Properly curing sweet potatoes before you store them is critical. In this expert guide, we discuss your curing options to extend your sweet potato harvest.
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You’ve sweated and toiled all summer caring for your sweet potatoes in the garden, or maybe you’ve grown sweet potatoes indoors. You’ve lovingly protected your plants from powdery mildew, stem rot, and sweet potato weevils. You were careful to harvest sweet potatoes gently, so they didn’t have any cuts or bruises, and now, it’s time to eat… almost.
You could certainly eat them right after picking if you really wanted to. But if you have a lot, don’t let them go to waste by not properly curing your sweet potatoes.
Curing sweet potatoes ensures that they have the right texture, taste just as sugar-sweet as you want them, and last you through the winter.
Curing is a process that transforms your produce by extending shelf life, preventing rot, and (in the case of sweet potatoes) improving flavor and sweetness. During curing, you create the ideal conditions to enhance your produce by adjusting temperature, humidity levels, and light exposure.
Storing is not the same as curing, and often the conditions for the two are very different. Each vegetable has unique curing needs, and here, we will cover how to cure sweet potatoes.
How to Cure Sweet Potatoes
Homegrown sweet potatoes are still alive even after being harvested and need oxygen. They continue to undergo a transformative process after harvest, during which starches convert to sugars, impacting the overall taste of your sweet potato.
A successful curing period results in that signature tasty sweet potato flavor. The initial curing process also allows sweet potatoes to heal any scratches or bruises that occurred during harvesting.
Before we talk about curing conditions, it is essential to note that you should not wash your sweet potatoes before curing. This will shorten their shelf life and result in a less successful cure. Instead, gently brush off any remaining dirt after harvesting.
Manage Temperature
Sweet potatoes initially need heat. Aim for high temperatures between 80 to 85°F (27-29°C) when curing sweet potatoes. The initial curing process takes 4 to 10 days. When your tuber feels firm and moist, it is done curing and ready to undergo the rapid transition to cooler temperatures. If it’s still soft to the touch, it may be best to enjoy the flavor of that sweet potato rather than spend more time trying to perfect the cure.
You can store your cured sweet potatoes at 55 to 60°F (13-16°C), but no colder, as cured sweet potatoes are sensitive to cold temperatures and could develop a chilling injury. However, this is a delicate balance, because temperatures higher than 60°F (16°C), combined with high humidity, can cause sprout development.
Check Humidity Levels
Sweet potatoes need a humid environment both during curing and in storage. During the curing process, maintain humidity levels of 90 to 95%. Make sure there is ventilation to allow the hot, moist air to circulate. When shifting to long-term storage, aim to maintain humidity levels around 85%.
Choose a Location
Creating these conditions for a curing location can be tricky, especially for home growers. But it shouldn’t be something you skip just because it’s difficult. The difference in taste alone between a cured and uncured sweet potato is motivation enough to go the extra mile and get creative. Below are some ideas to get the ball rolling.
Greenhouse
Greenhouses can be an excellent place to cure your sweet potatoes if you have one. You can easily monitor and control the temperature and moisture levels inside. For some regions, it may be too cold to cure sweet potatoes during the later harvest months unless you have a climate-controlled greenhouse, but if you do, this is a great option.
Bags
You can easily cure your sweet potatoes in a plastic bag to create humidity. After placing a handful of sweet potatoes inside, tie the bag closed and cut a few holes in the plastic grocery bag for ventilation. Then place your plastic bag either in a warm, sunny spot in your house or in a small, closed room with a space heater. This is a great, affordable option, but it can be difficult and time-consuming if you have many sweet potatoes to handle after harvest.
Confined Spaces
If you don’t want to go the plastic bag route and have a humidifier, this is an excellent option. Place your humidifier and space heater in a small closet or even a shower stall along with your sweet potatoes. It needs to be a closable space so that the damp air stays trapped inside. Depending on how long the process takes and how many sweet potatoes you harvest, this might not be practical if you need to use the shower or closet during this period.
Grow Tent
A grow tent is a great option for producing cured sweet potatoes. Add grow mats on each shelf to provide heat, along with a humidifier, and this is probably the most seamless way to cure sweet potatoes if you have enough space for a grow tent.
Near a Bucket of Water
I personally used this method for a couple of years before buying a humidifier for some of my houseplants, and it worked great. Placing a bucket of water in a warm, confined space near your sweet potatoes adds moisture to the air and creates humidity.
However, this is not a long-term solution for storing sweet potatoes afterward. When you need to decrease the temperature after the sweet potatoes have been properly cured, the bucket of water will no longer generate enough humidity, and your tubers could easily become damaged.
Oven
You can even use your oven to cure sweet potatoes. Some people use a low-temperature oven, but all you really need is an oven with a warming light. The light from the oven generates enough heat to reach the required temperatures in the small enclosed space.
For humidity, place a pan or oven-safe container filled with water at the bottom of your oven. Once the oven reaches the correct temperature range, put trays of sweet potatoes inside. Place a wooden spoon (or something similar) in the door to keep it slightly open so that the heat doesn’t continue to rise.
Monitor
Some of these suggestions make it more difficult to control heat and moisture levels during the sweet potato curing process. Variations in temperature and humidity mean that your curing timeline may not be universal. A slightly cooler temperature will result in a longer curing time and vice versa. Check your sweet potatoes for firmer skin to determine when they are ready.
Once you’ve completed the curing process, tuck your sweet potatoes into a root cellar or another dark location in a single layer. If you don’t have a root cellar, store them somewhere dark, cool, and moist. If stored properly and kept cool enough, your sweet potatoes will remain ready for use for months!
Frequently Asked Questions
Do sweet potatoes need to be cured before eating?
Technically, curing is not necessary. You can pick these tubers off the vine and eat them the same day—they just won’t have that signature sweetness. However, we highly recommend curing and storing sweet potatoes to allow the starches to convert into sugars, enhancing their flavor and extending their shelf life.
How do you cure sweet potatoes in the oven?
A more detailed explanation is provided above, but in summary: use a low-temperature oven, set it to a ‘keep warm’ cycle, or use one with a warming light. You will also need an oven-safe pan filled with water and something to prop the oven door open slightly to ensure your sweet potatoes don’t accidentally cook.
Can you leave sweet potatoes in the ground over winter?
This depends on where you live, but for the most part, no. Sweet potatoes are not tolerant to cold temperatures, and although soil can provide some insulation, it’s typically not enough. Frost will damage the roots, and chilling injury occurs when soil temperatures drop below 50°F (10°C), resulting in internal decay. Use a digging fork to gently harvest your potatoes from your raised bed or other garden space, brush off most of the soil from the dangling roots, and protect your harvest before the first frost hits. When the weather once again gets warm, you can put the roots back out in the garden to start new vines.
