You buy a big bag of potatoes, and three weeks later half of them have pale shoots and soft skins. Grandmothers who kept potatoes firm all winter weren’t lucky: they followed a few simple storage rules. Here they are, with the famous apple trick and what science actually says about it.
In short
- Cool: around 40 to 46°F, never near the stove.
- Dark: light turns potatoes green and wakes them up.
- Breathing, not sealed: a paper bag, a basket or a perforated bag.
- Unwashed and away from onions.
Why potatoes sprout
A potato is a living thing. Warmth and light tell it that spring has come, and it does what it’s built to do: it sends out shoots. Light also turns the skin green, a sign of solanine, a natural compound that tastes bitter and can cause stomach upset in larger amounts. Cut green patches and sprouts away generously before cooking. A potato that is heavily green or shriveled belongs in the compost.
Grandma’s rules, confirmed by the experts
- Keep them cool: Oregon State University Extension recommends 40 to 46°F. Above that, they sprout and shrivel sooner; below 38°F, they turn sweet. A cool basement, an unheated closet or an insulated garage that never freezes works well.
- Keep them dark: a paper bag, a cardboard box or a basket with a cloth over it.
- Let them breathe: never seal them in a closed plastic bag, which traps moisture and invites rot. A perforated bag or a basket is ideal.
- Don’t wash them before storing: brush off the dirt if needed, and make sure they are completely dry.
- Keep them away from onions: onions give off moisture and gases that speed up spoilage, so store the two apart.
- Sort them regularly: one rotting potato spoils its neighbors. Check the bag once a week.
The apple in the bag: folklore or science?
The famous grandmother’s trick is to tuck an apple in with the potatoes. There is some logic behind it: apples release ethylene, a natural plant gas, and continuous ethylene treatment is used in some commercial potato stores to hold back sprouting. But a single apple in a kitchen bag is nothing like a controlled commercial store, and results at home are inconsistent. Consider it a cheap, harmless test rather than a guarantee, and replace the apple as soon as it starts to wrinkle. Cool and dark will always do more than any apple.
And the fridge?
Here the advice has changed. For years, the rule was never to refrigerate raw potatoes, because cold turns some of their starch into sugar, which could brown more when fried. In 2023, the U.K.’s Food Standards Agency updated its guidance and now says raw potatoes can be stored in the fridge, after research found it doesn’t increase that risk compared with a cupboard. Oregon State also lists a fridge set around 40 to 46°F as a suitable option. If your kitchen is warm and you have no cool spot, the fridge beats a sprouting potato. Some people find the taste slightly sweeter.
The limit
Even well stored, potatoes don’t last forever: a few weeks in a kitchen, a few months in a real cool cellar. Store-bought potatoes are also sometimes already older than they look. Buy in smaller quantities if you don’t have a cool, dark place.
Small storage habits make a big difference in the kitchen, like lining your drawers with aluminum foil or the paper test for your fridge door. And some kitchens are even saying goodbye to the microwave.
Cool, dark, dry, away from the onions, with an apple if you like. That’s what kept a cellar full of potatoes firm until spring. That’s the trick.
I keep mine in a fridge with a temperature set at 40 degrees fahrenheit, with apples in the same fridge. Never have had any bad potatoes.