How Long Do Onions Last?

How long do whole onions last in storage?

Whole yellow and white onions last 1-3 months when stored in a cool, dry, well-ventilated location around 45-55 degrees F. The papery skin acts as a natural barrier against moisture loss and bacterial entry. Store onions in mesh bags, wire baskets, or breathable containers rather than sealed plastic bags; airflow prevents the humidity buildup that causes mold and sprouting. Sweet onions like Vidalia, Walla Walla, and Maui spoil faster (2-3 weeks) due to higher water content; these benefit from individual wrapping in paper towels to absorb moisture. Red onions last 1-2 months, slightly less than yellow onions. Never store whole onions in the refrigerator; the cold humidity accelerates sprouting, softening, and rot. Pantries, basements, and root cellars work best.

How long do cut onions last in the fridge?

Cut or peeled onions last 7-10 days in the fridge stored in airtight containers. The cold slows enzymatic browning and bacterial growth, but the strong odor can transfer to other refrigerated foods if the container isn't fully sealed. Use glass containers with tight lids or double-bag in plastic to contain the smell. Diced or sliced onions last 5-7 days; the increased surface area accelerates drying and oxidation. Cooked onions last 3-5 days refrigerated; the cooking process kills surface bacteria but the moisture-rich texture supports new bacterial growth. For longer storage, freeze cut onions in freezer bags for 6-8 months; frozen onions work well in cooked applications but lose their crispness for raw use. The flavor stays intact during freezing.

Why shouldn't onions be stored with potatoes?

Onions and potatoes both release moisture and gases during storage that accelerate each other's spoilage. Onions release ethylene gas, which causes potatoes to sprout faster and develop a bitter taste. Potatoes release moisture, which makes onions soften and mold. The combined effect cuts the shelf life of both by 50 percent or more. Store onions and potatoes in separate locations, both cool and dark but with good ventilation. Onions also shouldn't be stored near other ethylene-sensitive produce like apples, pears, and avocados. The traditional kitchen-vegetable basket holding multiple produce types in one bowl isn't ideal for long-term storage; it's fine for short-term display of items you'll use within a week.

How can you tell when onions have gone bad?

Bad onions show several clear signs: soft or mushy texture when squeezed (a fresh onion should feel firm throughout), dark or brown spots on the layers visible after peeling, sour or fermented smell instead of the sharp characteristic onion aroma, visible mold (often black, blue, or white) on the skin or exposed layers, or excessive sprouting with green shoots emerging from the top. Small soft spots can sometimes be cut away if the rest of the onion looks and smells normal; widespread softness means discarding the entire onion. The outer papery skin naturally dries and flakes over time, which isn't a sign of spoilage. Onions with green sprouts are still safe to eat (just remove the sprouts) but the flavor becomes more bitter. Slimy texture indicates bacterial growth and means immediate discard.