How to Store Potatoes, Onions, and Garlic for Weeks

To store potatoes, onions, and garlic for weeks or even months, keep all three in the dark and give them air, but give each its own temperature and humidity. Potatoes want it cool and humid, while onions and garlic want it cool and dry after a curing step. Get the conditions wrong and potatoes sprout, onions rot, or garlic dries out.

The good news is that university extension services have published clear guidance for all three, and it comes down to temperature, humidity, light, and air flow.

Potatoes want it cool, dark, and humid

Iowa State University Extension recommends storing potatoes at 40 degrees Fahrenheit with 90 to 95 percent relative humidity, in the dark. Light exposure turns the skins green, so a dark pantry, cellar, or cabinet is the right home.

Temperature is the critical dial. Iowa State says that above 50 degrees, tubers may begin to sprout in two to three months. Below 40 degrees, potatoes develop a sugary, sweet taste, which is why raw potatoes should not go in the refrigerator. At the recommended conditions, Iowa State puts the average storage life of potatoes at 5 to 8 months.

Keep potatoes away from apples and other ripening fruit. Iowa State notes that ethylene gas from ripening fruit promotes sprouting in potatoes, so the fruit bowl and the potato bin should live apart.

Your storage setup in one table

Produce	Temperature	Humidity	Light and air	Keeps about
Potatoes	40°F	90-95%	Dark	5-8 months
Onions	32-40°F	65-70%	Dark, ventilated	5-8 months
Garlic	32-40°F	65-70%	Dark, ventilated	6-7 months

These figures come from Iowa State University Extension and are averages. Storage life depends on the variety and on how well the crop was cured, so treat the last column as a guide, not a promise.

Onions and garlic need curing first, then cool and dry

Onions and garlic start with a step potatoes skip: curing. Iowa State advises curing onions for two to three weeks in a warm, dry, well-ventilated space, until the tops and necks are thoroughly dry. Cut the tops about one inch above the bulb, and use breathable containers such as a mesh bag, old nylon stocking, wire basket, or crate so air can circulate.

After curing, Iowa State recommends storing onions at 32 to 40 degrees Fahrenheit with 65 to 70 percent relative humidity. Variety matters: the extension guide notes that some varieties keep for months while others last only a few weeks, so use the weaker keepers first.

Garlic follows a similar pattern. Dry it in a warm, dry, ventilated spot, then store it at 32 to 40 degrees with 65 to 70 percent humidity. Trim the foliage and roots before storage and keep the bulbs where air can reach them. Iowa State puts the average storage life of garlic at 6 to 7 months.

Keep potatoes and onions apart

Potatoes and onions should be stored separately. The University of Melbourne explains that gases given off by onions speed up spoilage in potatoes, while the higher moisture of potatoes harms onions. Give each its own ventilated container in a dark spot, and both will last longer.

This also makes inspection easier. When each crop has its own bin, you can see at a glance which one needs attention and which one is holding up.

Check, trim, and discard on a routine

Storage is not a set-and-forget task. When you reach for your produce, inspect it and remove anything soft, shriveled, or showing decay, because one bad piece can affect the rest. Iowa State advises discarding onions with signs of decay at curing time, and the same habit applies throughout storage.

Handle sprouted or green potatoes with care. Ohio State University Extension advises removing sprouts before eating and avoiding green potatoes, noting that greening signals sunlight exposure and a buildup of solanine, which can make people ill. Small green spots can be trimmed away. Before cooking, wash potatoes in clean water with a clean brush, skip the soap, and cook them thoroughly.

Why the refrigerator hurts raw potatoes

Iowa State says potatoes stored below 40 degrees develop a sugary, sweet taste. A standard refrigerator is set at 40 degrees or below, so it sits right at or under that threshold. The better move is to never refrigerate raw potatoes in the first place and use a cool, dark cabinet or cellar instead.

Cooked potatoes are a different story. Once cooked, they are perishable like any cooked food and belong in the refrigerator. The no-fridge rule applies to raw potatoes only.

Curing: the step that makes onions and garlic last

Curing sounds technical, but it simply means letting the outer layers dry so the bulb is protected during storage. For onions, Iowa State recommends two to three weeks in a warm, dry, well-ventilated spot. For garlic, the same warm, dry, ventilated treatment applies until the tops are dry.

Use breathable containers for the whole process and for storage afterward. Air circulation is the point: it carries moisture away from the bulbs instead of trapping it. If a plastic bag or sealed tub is the only option on hand, it is better to use the bulbs soon than to store them that way.

A simple routine to follow

Pick one spot for potatoes and a separate spot for onions and garlic, and label the bins if it helps. Check each bin whenever you cook, pull out anything soft or sprouting, and use the oldest produce first.

Match each vegetable to its row in the table, check your stock regularly, and the pantry will stay fresher with less waste.