Potatoes start sprouting when they’re stored above 50°F, exposed to light, or trapped in moisture. Keep them cool, dark, dry, and well-ventilated, and most varieties will last months without a single sprout. Here’s exactly how to set that up.
The Right Temperature Range
Temperature is the single biggest factor. Potatoes stored above 50°F will begin sprouting within two to three months. The ideal long-term storage temperature is right around 40°F, with humidity between 90 and 95 percent. That combination keeps tubers firm without drying them out.
A basement, unheated garage, or root cellar often hits this range naturally during cooler months. If you’re storing potatoes in a pantry at normal room temperature (around 68–72°F), expect them to sprout much faster, sometimes within a few weeks depending on the variety. The cooler you can get without going below about 42°F, the better.
There’s a catch with going too cold. Storing potatoes below 46°F (and especially at refrigerator temperatures around 38°F) triggers a process called low-temperature sweetening, where starches convert rapidly into sugars. In one study, potatoes stored at 39°F for just 15 days saw their sugar content jump nearly 28-fold. Those extra sugars react with amino acids during frying or roasting to produce acrylamide, a compound classified as probably carcinogenic. So while your fridge will stop sprouting, it creates a different problem if you plan to cook at high heat. If you do refrigerate potatoes, letting them sit at room temperature for a week or two before cooking can partially reverse the sugar buildup.
Keep Them in Total Darkness
Light does two things to potatoes, both bad. It accelerates sprouting, and it triggers the production of chlorophyll (the green color under the skin) along with solanine, a naturally occurring toxin. Research on fluorescent light exposure found that potatoes began greening after just two hours, with noticeable green patches after three hours and intense greening after seven. Fluorescent and LED lights with concentrated blue and red wavelengths are actually worse than sunlight for this process, so a bright kitchen counter under overhead lights is one of the worst places to store potatoes.
Even brief, repeated exposure adds up. If your potatoes sit on an open shelf that gets light whenever you flip on the kitchen switch, that daily exposure compounds over days and weeks. A closed cabinet, a paper bag, or a covered bin in a dark corner solves this completely.
Best Containers for Storage
Potatoes need airflow. Without it, moisture builds up on the skin and creates conditions for soft spots, mold, and rot. But too much airflow dries them out and causes wrinkling. The goal is gentle ventilation with light blocked.
In a side-by-side test of five storage methods over 10 days, a plain paper bag came out on top. The potatoes inside were the firmest of all groups, with zero signs of greening, sprouting, or moisture problems. Paper blocks light completely while still letting air exchange happen, and it absorbs excess surface moisture without trapping humidity.
Mesh bags performed almost as well, keeping potatoes firm with excellent air circulation, though they offer less light protection. If you use a mesh bag, store it inside a dark cabinet or closet.
The worst performer was the plastic bag potatoes come home from the store in. Plastic traps just enough moisture to create a clammy environment, and after 10 days potatoes in plastic were noticeably less firm with early soft spots forming. If your potatoes come in a sealed plastic bag, transfer them as soon as you get home. A cardboard box with a few holes punched in the sides also works well.
Keep Potatoes Away From Onions and Fruit
This common advice is backed by real science. Onions, apples, bananas, and other ripening fruits release ethylene gas, a plant hormone that shortens potato dormancy and triggers earlier sprouting. Research published in Plant Physiology confirmed that even low concentrations of ethylene markedly shorten the rest period of potato tubers. A 1932 study first documented that volatile compounds from apples alone were enough to inhibit normal dormancy in stored potatoes.
The effect is straightforward: ethylene essentially tells the potato that conditions are right to start growing. Store your potatoes in a separate area from your fruit bowl and your onion basket. Same pantry is fine, just not the same bag or bin.
Don’t Wash Before Storing
It’s tempting to rinse dirt off potatoes before putting them away, but residual moisture on the skin promotes bacterial and fungal growth. Oregon State University’s extension service recommends storing potatoes with dry soil still on them and only washing right before cooking. If potatoes are caked in mud, brush off the excess with a dry cloth or soft brush, but skip the water.
Before putting potatoes into long-term storage, sort through them and pull out any with cuts, bruises, soft spots, or signs of disease. Use those first, within a few weeks. Damaged tubers don’t store well and can spread decay to healthy ones sitting next to them.
Curing Homegrown Potatoes
If you grow your own potatoes or buy them from a farm, curing before storage makes a significant difference. Curing toughens the skin and heals small nicks from harvesting, which extends storage life considerably. The process is simple: spread the potatoes out in a dark, well-ventilated space at 50 to 60°F with high humidity (85 to 90 percent) for 7 to 10 days. After curing, move them to your cooler long-term storage spot at around 40°F. Store-bought potatoes have typically already been cured before reaching shelves.
Some Varieties Last Longer Than Others
Not all potatoes have the same built-in clock before sprouting. Each variety has a natural dormancy period, the window after harvest during which the tuber won’t sprout regardless of conditions. Thick-skinned varieties like Russets tend to have longer dormancy periods and store the best, often lasting four to five months under good conditions. Yukon Golds and other yellow-fleshed varieties fall in the middle. Thin-skinned potatoes like reds and fingerlings have shorter dormancy and should be used sooner.
Research comparing long-dormancy and short-dormancy potato varieties found that long-dormancy types maintained stable starch and sugar levels throughout storage, while short-dormancy types showed volatile metabolic changes that led to earlier sprouting. The practical takeaway: if you’re buying potatoes in bulk to store for weeks or months, choose Russets or other thick-skinned varieties.
What to Do With Sprouted Potatoes
If your potatoes do sprout despite your best efforts, they’re not necessarily ruined. A potato that’s still firm with small sprouts is safe to eat once you snap off the sprouts completely. The sprouts themselves concentrate solanine and should always be discarded. If the potato has turned green under the skin, gone soft, or has extensive sprouting, throw it out. Solanine is toxic even in small amounts, and cooking does not break it down.
Green coloring is a visible warning sign, but the toxin itself is colorless, so peel generously around any green areas. If a potato tastes bitter, stop eating it. That bitterness signals elevated solanine levels.
Quick Storage Setup
- Temperature: 40–50°F is the sweet spot. Above 50°F, expect sprouting within weeks.
- Light: Total darkness. Even a few hours of light exposure starts the greening process.
- Container: Paper bag, cardboard box, or mesh bag in a dark space. Never sealed plastic.
- Humidity: 90–95 percent for long-term storage. A basement naturally provides this in most climates.
- Neighbors: Keep away from onions, apples, and bananas.
- Moisture: Don’t wash until you’re ready to cook.