So you decided to plant potatoes this year! You’re excited and confident until you go to pull your seed potatoes out of storage and…they’re shriveled. Does that mean they’ve all gone bad? Will squishy, wrinkled potatoes actually produce healthy potato plants?
Yes, you can plant shriveled potatoes. Even though shriveled seed potatoes don’t look appetizing, they are still fully capable of growing healthy plants. As long as your potatoes have viable eyes and no signs of blight, no one will be able to tell that your seed potatoes were shriveled.
Shriveled potatoes can be a good sign
While shriveled potatoes look like the last thing to exhibit life, shriveled seed potatoes don’t spell the end of your potato patch. Potatoes are vigorous growers that don’t go down without a fight (potatoes will sprout nearly anywhere, after all).
If your shriveled-up seed potatoes have started sprouting, it’s a sign that the seedlings are using up the food stores in the potatoes, which is exactly what the starchy potatoes are designed to do in the first place. Even if your potatoes are wrinkled or slightly squishy, so long as each piece has an eye, your potatoes will rehydrate once planted and grow healthy potato plants.
If you’re within a month or so of your area’s potato planting date, you can encourage the sprouting even more by chitting (or pre-sprouting) your potatoes. If it’s still too early, move your potatoes to a cooler and darker location to slow down the sprouting process.
How to chit (or pre-sprout) potatoes
Regardless of whether your seed potatoes are wonderfully fresh or slightly shriveled, pre-sprouting your seed potatoes will save you time and will jumpstart your potato crop. This process of pre-sprouting potatoes, called chitting, is as simple as moving your seed potatoes from cold storage to a warm, humid environment with abundant light to encourage the eyes to start sprouting.
Chitting isn’t an essential step of the potato-growing process, but it does help by identifying which potatoes will sprout and giving the potatoes a headstart before they go into the garden. Chitting potatoes is similar to starting seeds indoors in this regard – it isn’t essential, but it does extend your season considerably.
You’ll want to start chitting potatoes about a month before you plan to plant them. Potatoes can go in the ground between two and four weeks before your average last frost date, so identify that date and count backward from there.
Gather your seed potatoes together and lay them out in a box or tray, single layer, eyes and sprouts pointing up. Leave your potatoes alone in a warm but dark room for two weeks, and then move your potatoes to another cooler room with some light and leave them for two more weeks.
When you go to check on your potatoes that second time, you’ll notice that the eyes have sprouted and your potatoes are chitting! They might start to look a little shriveled–but as previously discussed, it’s no problem.
Now it’s time to plant your shriveled (but chitted!) potatoes.
How to plant potatoes
Before planting seed potatoes, you’ll want to cut each potato into a few smaller pieces, saving two eyes on each piece. Allow the cut pieces to dry out and form a callous before planting.
If you haven’t already, prepare your soil for planting by adding compost and a balanced fertilizer. Potatoes thrive in slightly acidic to neutral soil, so if you suspect that your soil is more alkaline, do a pH test to confirm and adjust if needed.
Next, dig a trench six to eight inches deep, unless you’re planting potatoes in a container or raised bed. Place each seed potato piece in the trench, at least a foot apart. After you’ve sown all the seed potatoes, fill the trench with soil, covering the seed potatoes with at least four inches of soil.
As the potato plants sprout and grow larger, you’ll need to add additional soil to the rows, eventually mounding up the soil. These “hills” warm the soil slightly and increase drainage, but the most important thing hilling does is protect potatoes from being exposed to sunlight, causing the tubers to turn green and store the toxin, solanine, which is harmful to humans.
Beware of soft potatoes
While planting shriveled potatoes is perfectly fine, you’ll want to avoid planting any seed potatoes that are soft, have brown or slimy flesh, and are obviously rotten.
The best way to prevent rotten seed tomatoes is to use sterile equipment and hands when harvesting potatoes in summer. An ounce of prevention is worth a pound of cure, so if you see any rotten or blight-riddled potatoes in the field, toss them out, or better yet–bag them up and throw them in the garbage.
If you come across rotten tubers in storage, throw them away immediately and keep an eye on the rest of your stash to make sure that the rot doesn’t spread to any other tuber.
Storebought potatoes are treated with a sprout inhibitor
How is it that grocery store potatoes keep so long compared to homegrown potatoes? I’ve found that I can forget about storebought potatoes for weeks, if not months, and when I do recover my long-lost potatoes there’s only slight sprouting, if at all.
Commercially stored potatoes have been treated with a sprout inhibitor to prevent sprouting. Be sure to rinse storebought potatoes thoroughly before cooking them, and if you decide to use grocery store potatoes as seed potatoes, all you need to do is wash away the sprout inhibitor. Eventually, even storebought potatoes will sprout and you can successfully plant those potatoes.
Potatoes are still alive when they are harvested, and the tubers “breathe” by exchanging oxygen and carbon dioxide with their immediate environment.¹ When commercial potatoes are treated with the sprout inhibitor, it interferes with that process and actually preserves the potato.
Because grocery store potatoes are protected with the inhibitor, they are far less likely to sprout, and so these potatoes won’t wrinkle or shrivel the way that homegrown potatoes do. It’s primarily the chemical reaction between the sprouts and the starchy potato that cause wrinkling – a telltale sign that sprouts are using the potato’s food stores to grow.
Properly store potatoes to minimize shriveling
For the longest shelf life with your homegrown spuds, keep the tubers in a cool and dry place, out of direct sunlight. Store your potatoes in an open paper bag or a mesh bag to allow for adequate airflow.
If you have a cellar, keep your potatoes there, and if you don’t have a cellar, aim to store your potatoes in the pantry or even a drawer. Just don’t keep potatoes anywhere near onions, apples, or bananas as these foods might actually cause potatoes to sprout sooner.
There are several options (other than a root cellar) for storing potatoes. Reference this article for the best storage solutions for root vegetables. You can use a dry basement, an insulated garage or shed, and even an unheated attic to store your root vegetables safely.
When you harvest potatoes, leave a layer of dirt and allow them to cure in the summer heat for a day or two before packing them away. Store potatoes in boxes or crates, and keep in a dark place that sees about 85% humidity for the best-looking potatoes. Potatoes should keep for five to eight months if stored properly!
Shriveled potatoes are nothing to worry about, and are probably just a reflection of how the tubers were stored. As long as you can see eyes, even the most wrinkled seed potatoes will produce a glorious harvest of potatoes in the garden this summer.
¹ Hard, Lindsey-Jean. “How to Store Potatoes So They Last for Months (Yes, Months)” Food 52, Food 52. 9 Aug 2021, https://food52.com/blog/14613-the-best-way-to-store-potatoes.