Potatoes keep longest cold, dark, and humid, but not as cold as a refrigerator used to be blamed for. A cool cupboard, box, or cellar at 40-46°F (4-8°C) with high humidity and some airflow will hold table potatoes for weeks to months, according to Iowa State University Extension and Outreach and Oregon State University Extension. Keep them out of the light, away from onions, and in a container that isn’t sealed airtight. Store-bought bags already have most of that sorted; a home-grown harvest needs curing first. The rest of this guide covers the exact numbers, why potatoes turn green, whether the fridge is actually off-limits now, and how long a batch realistically lasts.
What temperature and humidity keep potatoes fresh longest?
Potatoes are living tubers that keep respiring in storage, so both heat and cold work against them in different ways. Too warm and they sprout and shrivel; too cold and their starch converts to sugar, a process extension publications call “cold sweetening,” which affects taste, browning color, and texture when cooked. The combination that minimizes both problems is cool, not cold, and humid enough that the tubers don’t dehydrate.
| Stage | Temperature | Humidity | Duration |
|---|---|---|---|
| Curing (after harvest) | 50-65°F (10-18°C) | 85-90% | 7-14 days |
| Table-use storage | 40-46°F (4-8°C) | 90-95% | Weeks to a few months |
| Seed potato storage | Below 40°F (4°C) | 90-95% | Through winter |
| Below 38°F (3°C) | — | — | Avoid: causes sweetening |
Iowa State Extension and Oregon State University Extension both put long-term storage in the 40-46°F range with high humidity, while University of Idaho Extension notes that potatoes destined for frying or chipping are generally held nearer 45-50°F because cold storage raises the sugar content that browns and darkens during frying. Seed potatoes, which aren’t going to be eaten until next year’s planting, can run colder since flavor and fry color don’t matter for them. Good ventilation matters almost as much as temperature: stagnant, humid air around a pile of tubers is exactly the condition that lets rot spread from one damaged potato to its neighbors.
Should you store potatoes in the fridge?
For years, the standard advice was no. The UK’s Food Standards Agency used to recommend against refrigerating raw potatoes headed for frying, baking, or roasting, on the theory that fridge temperatures cause cold sweetening and that the extra sugar then raises acrylamide, a compound linked to cancer risk in animal studies, when the potato is cooked at high heat. The FSA has since reviewed newer research on home storage and revised that guidance, concluding that fridge storage does not meaningfully raise acrylamide-forming potential compared with a cool, dark cupboard, according to the FSA’s current acrylamide guidance. Consumers in the UK are now told either option is acceptable, and that refrigeration can actually extend shelf life and cut food waste.
In practice, that leaves a reasonable middle ground for a home kitchen that runs warmer than 50°F (10°C) in storage areas, or has nowhere cool and dark to put a cupboard box: the fridge crisper is an acceptable fallback, not a failure. If you do fry or roast fridge-stored potatoes, letting them sit at room temperature for a day or two beforehand gives some of the sugars time to convert back to starch. A cool pantry, closet, or unheated room still beats either extreme for texture and flavor, and it’s the only practical option for seed potatoes or a large homegrown harvest that won’t fit in a refrigerator.
Why shouldn’t potatoes be stored near onions?
Potatoes and onions are both classic root-cellar vegetables, which makes it tempting to store them in the same bin, but extension sources advise keeping them apart. Onions give off moisture and gas as they’re stored, and that combination speeds up sprouting and softening in nearby potatoes; the reverse also holds, since potatoes release moisture that can make onions go moldy faster. Our guide to storing food to prevent waste covers the broader pattern of ethylene-producing produce that shortens the life of whatever sits near it, the same reasoning that keeps apples away from other produce in the fridge. The fix is simple: separate bins, baskets, or drawers, even if they’re both headed for the same dark cupboard.
How do you stop potatoes from turning green or sprouting?
Light is the trigger for both problems. Potatoes exposed to light produce chlorophyll, which turns the skin and flesh green, and at the same time produce more solanine, a natural glycoalkaloid that’s mildly toxic and bitter-tasting, according to University of Alaska Fairbanks Cooperative Extension. The green color itself isn’t the toxin, but it’s a reliable warning sign that solanine levels have risen. Extension guidance is to store potatoes somewhere genuinely dark with good air circulation, and to treat a greened potato by cutting away the green area generously before cooking the rest; a potato that’s extensively green throughout should be discarded rather than trimmed.
Sprouting is a related but separate issue, driven more by warmth and age than light. A sprouted potato is still usable if the sprouts are small: snap them off and inspect the area underneath, since the sprouts and any skin that has greened or softened around them also concentrate glycoalkaloids. A potato that’s heavily sprouted, soft, or shriveled throughout is better composted; if you keep a bin, our guide to starting a compost pile covers how raw vegetable scraps like peels and culled potatoes break down.
How do you cure potatoes you grew yourself?
Store-bought potatoes have usually already been cured by the grower, but a home harvest needs the step done before it goes into long-term storage. Curing lets the skin thicken and minor wounds from digging seal over, both of which cut down on moisture loss and rot once the potatoes are in storage. Oregon State University Extension recommends letting the foliage die back before digging, then curing unwashed, brushed-off tubers in a dark, well-ventilated space at moderate temperature and high humidity for 7 to 10 days; Iowa State Extension gives a similar window of 50-60°F with 85-90 percent humidity for about two weeks. After curing, move potatoes to the cooler, more humid conditions of long-term storage described above, in single layers or shallow crates rather than one deep pile, which keeps bruised or rotting tubers from being hidden under good ones.
Skip washing potatoes before storage; water encourages rot, and any soil still clinging to the skin can be brushed off right before cooking instead. Set aside any tuber that’s cut, bruised, or insect-damaged from the curing batch and use it first, since damaged skin won’t seal the way an intact one will.
How long do stored potatoes actually keep?
Storage life depends heavily on how the conditions above are met, and on variety: thinner-skinned new potatoes don’t keep as long as mature, thick-skinned storage varieties like russets.
| Storage method | Typical keeping time |
|---|---|
| Room temperature, counter | 1-2 weeks |
| Fridge, uncured or store-bought | 3-5 weeks |
| Cool, dark cupboard (40-46°F, humid) | 2-3 months |
| Cured homegrown, root cellar conditions | 4-6+ months for long-keeping varieties |
| Cooked and refrigerated leftovers | 3-5 days |
Check stored potatoes every couple of weeks and remove any that have softened, sprouted heavily, or started to rot, the same habit that keeps one bad tuber from spreading decay through a whole box. For how other refrigerated staples compare, our reference chart of how long food lasts in the fridge covers cooked potatoes and other leftovers in more detail. Handled this way, a bag from the store or a backyard harvest both go a lot further than a few days on the counter would get them, with far less of it ending up in the trash before it’s used.