Curing sweet potatoes in the sun

The process for harvesting, curing, and storing sweet potatoes is simple once you get the hang of it, but there are a number of steps to know about. Here’s your step-by-step guide to having delicious, homegrown sweet potatoes in time for Thanksgiving Dinner.

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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, so watering is only essential for keeping the soil from being bone-dry. In other words, this crop is great for a 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 to grow vertically because they develop several big tubers at each root junction. In the more traditional garden approach, vines sprawl along the ground, producing a bunch of tiny potatoes as they try to root everywhere.

Sweet potato vines produce well when trellised to grow vertically.

How to Harvest Sweet Potatoes

Harvest any time after tubers have started to form; start checking late summer. I like to wait at least until the leaves start to yellow, which indicates that I’ve gotten the most production I can out of the vines that I’ve planted.

The key to a superior, sweet taste, however, is allowing them to experience a light frost, and then harvesting before a hard frost. So you may want to let them stay in the ground a little while longer and keep an eye on the weather.

Here’s the two-step process I use when harvesting my sweet potatoes.

Step 1 for Harvesting 

Choose a day when it hasn’t rained for a few days, that way the soil is minimally moist and crumbly, and 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.

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Step 2 for Harvesting 

This 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 loosen the soil around the tuber, digging under it to lift it out gently. I like to use my hori hori garden knife for this step.

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! (And here’s a great garden knife for right-handers.)

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. 🙁

It’s hard to wait, but the curing process really sweetens them up.

Gently loosen and lift the tubers using a garden knife or digging fork.

How to Cure Sweet Potatoes

Curing is a necessary step that sweetens the flavor and allows the skins to harden for optimal storage. Be patient and don’t rush the process!

The first step for curing sweet potatoes lasts about 10 days, and the second step lasts about six weeks.

Step 1 for Curing 

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 sugar production 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 solution for years now is this: Punch a few holes in plastic grocery bags 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.

After 10 days, open your plastic bags of curing tubers. They should be moist and much harder to the touch. Compost any soft ones.

While you can technically cook your sweet potatoes now, continuing with this next step kicks off even more sugar production and prepares them to store even longer.

A Georgia Jet sweet potato harvest.

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Step 2 for Curing

Curing for up to 6 more weeks makes the sweetest sweet potatoes.

Roll up each tuber separately in a single sheet of newspaper, stacking them in a cardboard or wooden box, or any breathable storage container. Place it in a basement or other room where the temperature is close to 55-60° F, for six weeks.

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 could otherwise ruin the harvest.

A makeshift root cellar in my basement includes a wooden box of curing sweet potatoes.

When can I cook homegrown sweet potatoes?

Follow my curing method described above for at least 10 days, and an additional 6 weeks after that, in order to cook tubers at the peak of sweetness.

So if you want to serve sweet potato casserole at your Thanksgiving Dinner, harvest in early October at the latest. You may not get that frost-kissed sweetness, but the curing process sweetens them up.

How to Store Sweet Potatoes

After curing, you can store them for 6-8 months in ideal conditions:

• Breathable container or mesh bag
• Cool temperature, around 55° F
• Dark
• Around 60% humidity

Actual storage length depends on post-harvest conditions. 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!

#1: When do you plant sweet potatoes?
Plant sweet potato slips in a sunny spot late in spring after all danger of frost has passed.

#2: When do you harvest sweet potatoes?
Sweet potatoes can be harvested any time tubers have formed, starting in late summer. However, allowing them to experience a light frost and then harvesting before a hard frost is the key to a superior, sweet taste. Harvest in early October if you’d like to sweeten them through curing in time for Thanksgiving.

#3: How do you preserve sweet potatoes after harvesting?
Sweet potatoes can be preserved through canning, dehydrating, or freezing.

They also store a long time in a cool, dry pantry, similar to regular potatoes, when first prepared through a curing process.

#4: Do you need to cure sweet potatoes before eating them?
While you can eat them immediately after harvest, they are sweeter after being cured.

#5: How long can you store sweet potatoes?
You can store cured sweet potatoes for 6-8 months in ideal conditions.

Are sweet potatoes one of your favorite crops? What is your method for harvesting, curing, and storing?

READ NEXT:

• Growing & Harvesting Beets Year-Round
• Protect Cold Weather Crops with a Cold Frame
• When to Harvest & How to Store Garlic

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