The process for harvesting, curing, and storing sweet potatoes is simple once you get the hang of it. Here’s how to do it.
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Growing Sweet Potatoes
Sweet potatoes are almost a set-it-and-forget-it crop, which is why they made my short list of low-maintenance crops!
Plant sweet potato slips late in spring after the danger of frost has passed, and harvest in the early fall.
This crop likes it sunny and hot. Watering is only essential for keeping the soil from being bone-dry. In other words, sweet potatoes don’t require a lot of watering, making it a wonderful crop for the water-wise garden.
They’re generally pest-free, too.
If you haven’t picked up on it yet, sweet potatoes are one of my all-time favorite crops!
I like to grow the variety ‘Georgia Jet’, which is a sweet, orange variety known to be high-yielding and accommodating of a variety of climates and soil types.
Sweet potato vines also produce well when trellised. That’s because when the vines are allowed to crawl on the ground, they’ll try to put roots in everywhere, which produces a gazillion teensy little potatoes, as opposed to putting all their energy into creating several big ones per vine.
Two Steps for Harvesting Sweet Potatoes
Sweet potatoes can be harvested any time tubers have formed (start checking late summer).
The key to a superior, sweet taste, however, is allowing them to experience a light frost, and then harvest before a hard frost. So you may want to let them stay in the ground a little while longer.
Step 1 for Harvesting Sweet Potatoes
To harvest, pick a day when it hasn’t rained for a few days. The soil should be minimally moist and crumbly so that you can brush off the tubers with a very light touch.
You don’t want mud caked onto the tubers because it makes them harder to clean and store.
The harvesting process starts with cutting the vines back so you can get to the soil. Growing sweet potatoes on a trellis makes it easier to follow the vines and find the location of the tubers.
Cut off the vines, leaving six-inch lengths above ground as a sweet potato beacon.
Are you looking for more strategies for your permaculture garden? You’ll find loads of information just like this in my award-winning book, The Suburban Micro-Farm.
Step 2 for Harvesting Sweet Potatoes
The next step is a delicate one. At this stage, the skins of the tubers are very thin and easily damaged. Carefully and slowly push away the soil to reveal the harvest treat.
Then I use my hori hori garden knife to loosen the soil around the tuber, digging under it to lift it out gently.
Interested in a garden knife? I still have the one my gardening mentor bought me–my own special left-handed one. It still looks like new today, more than ten years later!
Here are my picks:
Whether you’re using a hori hori knife, a digging fork, or a shovel for harvesting, don’t aimlessly stab into the soil, as you’ll risk cutting the tubers in half. Once you’ve found one, don’t pull it out, because the delicate gems will undoubtedly snap in half, leaving the other half buried.
Pieces of tubers won’t store as well as whole, unscathed potatoes.
So dig gently, find a tuber, loosen, and lift. Having loose soil really helps, so consider growing yours in a raised bed.
You’ve harvested your tubers and now you’re probably thinking that you’ll head straight to the kitchen to make a sweet potato casserole, right? Wrong. 🙁
So sorry to be the bearer of bad news, but your work is just getting started!
Two Steps for Curing Sweet Potatoes
The first step to curing sweet potatoes lasts about 10 days, and the second step lasts about six weeks.
Step 1 for Curing Sweet Potatoes
This first step for curing sweet potatoes heals any damage that occurred to the tubers during harvest so they store longer. It also kicks off the sugar production process to give you sweeter tubers.
For this step, the ideal scenario is an 85-degree room with 85% humidity. What? You don’t have that?!
My easy solution for years running now is this: take plastic grocery bags, punch a few holes in them, and fill them with a single layer of tubers in each bag. Tie the bags closed and put them in your sunniest, warmest window. This creates a sort of greenhouse effect.
Leave for 10 days.
If it gets chilly and your windows are drafty, put a blanket or towel over them to keep them warm.
Step 2 for Curing Sweet Potatoes
After 10 days, open your plastic bags of curing tubers. They should be moist and much harder to the touch. Toss out any soft ones.
You can technically cook with your sweet potatoes now, but continuing with step 2 kicks off even more sugar production and prepares them to store even longer.
Now, roll up each tuber separately in a single sheet of newspaper.
Stack the wrapped tubers in a cardboard or wooden box, or another storage container that allows aeration, and place it in a basement or other room where the temperature is as close to 55-60 degrees as possible, for six weeks.
Keep the lid off.
This six-week period develops the hard skin necessary for long term storage, and kicks off even more sugar production. The newspaper allows aeration and prevents moisture build-up that would otherwise ruin the crop.
When can I cook homegrown sweet potatoes?
After curing, they will be at the peak of sweetness and are FINALLY ready for you to cook with them! The shortest curing method takes 10 days, but they’ll be even sweeter if you cure them for an additional six weeks, as described in the ‘Curing Sweet Potatoes’ section above.
So if you want to serve sweet potato casserole at Thanksgiving, you’ll want to harvest in early October at the latest. You may not get that frost-kissed sweetness, but the curing process will help sweeten them up.
How long do sweet potatoes store?
If you’ve completed both steps above for curing, you can store them for 6-8 months with the lid on in ideal conditions:
- Cool temperature, around 55 degrees F
- Around 60% humidity
Actual storage length depends on how long they were cured and how ideal the storage conditions are.
The process for harvesting, curing, and storing sweet potatoes sounds complicated and time-consuming, but really it’s simple once you get the hang of it.
The taste of these homegrown, sweet orange gems that say ‘Thanksgiving’ is all you need to convince yourself to grow them year after year!
Are sweet potatoes one of your favorite crops? What is your method for harvesting, curing, and storing?