Sweet potatoes are one of the easiest and most productive crops to grow in a home garden, and they can last for many months in storage if the proper care is taken in harvesting and curing. Here, I’ll explain the simple steps and tricks to harvest and cure sweet potatoes successfully.
It generally takes about 120 days for sweet potatoes to mature after planting the slips, so once your slips are in the ground, mark your calendar for four months later. But this is not a hard deadline — watch the plants themselves to know the right time to harvest.
When you notice the foliage above ground is starting to yellow, you’ll know that production is slowing down. You can harvest at this point, but the longer you leave the sweet potatoes in the ground while the top growth is still viable, the larger the potatoes will be.
However, you shouldn’t wait too long to harvest sweet potatoes either. Once the top growth has died down — typically via a frost — you should harvest right away. If you aren’t prepared to dig up the sweet potatoes then and there, the next best thing is to cut off all the foliage. This is important because the top growth may carry a plant disease that can pass through the foliage down to the sweet potatoes and affect them as well.
After I have cut all the vines I prefer to get them out of the way to clear the path and give easier access while harvesting.
Next, I use a digging fork (also known as a garden fork) to get underneath the sweet potatoes and loosen up the soil. I do this gently because a sweet potato that has been damaged will most likely rot in storage. Avoid piercing the sweet potatoes or scraping off their very soft skin.
Once the soil has been loosened, your best tool for harvesting the sweet potatoes is your hands.
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.
Once the sweet potatoes are out of the ground, don’t leave them in direct sunlight for more than a few hours.
To prepare the sweet potatoes for storage, you can carefully wipe off the excess dirt right away, but it’s better to wait until they are a few days into the curing process. After a few days, the skin will have toughened up a little and will be less likely to come off as you are removing dirt. And never wash the sweet potatoes with water before curing or storing, as that will shorten their shelf-life.
In order to cure for long-term storage, sweet potatoes need high humidity and heat above 80 or 85 degrees for one to two weeks. To achieve these conditions, place sweet potatoes in a single layer in a plastic grocery bag. Tie the bag closed but also cut holes in the bag for ventilation. Once all your potatoes are bagged, place them in the sunniest spot in your house.
Alternatively, put the sweet potatoes in a closet (or a pantry or bathroom) with a space heater and a humidifier set to 85 or 90 percent humidity. If you don’t have a humidifier, leave a bucket of water in the closet instead. Place a thermometer that also reads humidity in the closet to keep an eye on it.
If you follow these simple steps, you’ll enjoy sweet potatoes for many months ahead.
Have you had success curing sweet potatoes? Let us know in the comments below.
Links & Resources
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!
joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.
*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Park Seed, and Exmark. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.