How to Store Onions
Onions last months if you get three things right: dry, dark and ventilated. Put them in the fridge or next to potatoes and they will rot or sprout within weeks.
The conditions
| Factor | Target | Why |
|---|---|---|
| Temperature | 4–10°C | Above 10°C they sprout; near freezing they soften |
| Humidity | Low — 65–70% | Damp air causes neck rot |
| Light | Darkness | Light triggers sprouting |
| Airflow | Good | Trapped moisture rots the whole net |
What not to do
- Do not refrigerate whole onions. The cold and humidity make them soft and mouldy. (Cut onions should go in the fridge.)
- Do not store with potatoes. Each makes the other sprout faster — potatoes release moisture, onions release ethylene.
- Do not use a sealed container. No airflow means rot.
- Do not wash them. Water on the skin invites mould.
- Do not pile them deep. Pressure bruises the ones at the bottom.
How to store them
- Cure first. If home-grown, dry them in a warm airy place for 2–3 weeks until the necks are papery and the skins rustle.
- Leave the skins on and do not trim the root end — that is the seal.
- Use a mesh bag, net, or a basket with holes. Hang it if you can.
- Keep in a dark, dry place — a cupboard, garage or cellar.
- Check weekly and remove any soft or sprouting ones immediately. One bad onion spreads.
Storage times
| Type | Method | Time |
|---|---|---|
| Yellow / storage onions | Cool, dry, dark, ventilated | 4–6 months |
| Red onions | Same | 3–4 months (shorter) |
| Sweet onions (Vidalia) | Same | 4–6 weeks only |
| Spring onions / scallions | Fridge, wrapped | 1–2 weeks |
| Cut onion | Fridge, airtight | 7–10 days |
| Chopped, frozen | Freezer bag | 6–8 months |
Why onions rot
Two main causes:
- Neck rot — a fungal infection that enters through an uncured or damaged neck. The onion goes soft from the top down.
- Bacterial soft rot — a slimy, foul-smelling breakdown, usually from bruising or storage in damp conditions.
Neither is salvageable. Remove affected onions at once.
Can you freeze onions?
Yes, and it works well. Chop them, spread on a tray to freeze individually, then bag. They keep 6–8 months and go straight into cooked dishes — no need to thaw.
Frozen onions are soft, so they are unsuitable for raw use.
What about sprouted onions?
A small green shoot means the onion is using its stored energy. It is safe to eat but will be softer and milder. Use it soon in cooked dishes.
If it is soft, slimy or smells wrong, discard it.
Common questions
Should onions be stored in the fridge?
No for whole onions - cold and humidity make them soft and mouldy. Yes for cut onions, which should be wrapped and refrigerated for up to 10 days.
Can you store onions and potatoes together?
No. Potatoes release moisture and onions release ethylene, and each makes the other sprout faster. Keep them in separate places.
How long do onions last?
Yellow storage onions last 4-6 months in cool, dry, dark, ventilated conditions. Red onions 3-4 months, sweet onions only 4-6 weeks.
Why are my onions sprouting?
Warmth and light. Keep them below 10C in complete darkness with good airflow, and away from potatoes.
Storage times for potatoes, garlic, rice and 20 more staples: Food Storage Time Lookup.