How to Store Onions to Avoid Sprouting or Softening

Storing onions correctly will help prevent them from sprouting or going soft before you get a chance to use them. If you found a great deal on onions or had a great onion harvest here’s what you need to know to keep them at their best for as long as possible.

A beautiful bounty of onions, deserves to be kept at their best as long as possible.

Also Read: How to Dehydrate Onions, How to Freeze Onions, How to Harvest Onions

The Right Conditions for Storing Onions

Onions keep very well under the right conditions. For dry bulb onions (white, yellow or red) this means:

  • Cool.  Preferably 4- 10°Celsius or 40-50° Fahrenheit; just above fridge temperature and below room temperature.  Too hot (your kitchen pantry) and your onions will sprout.  Too cold (your fridge) and your onions will go soft and start tasting funny.  A cool room, the basement or a spot in the garage (when temperatures are above freezing) are good storage places.
  • Dry.  Onions pick up moisture very easily which will lead to rot. Keep them in a mesh bag, old nylons or open basket in a dry place. If you have high humidity, it’ll be tricky to keep onions for a long time.  If you do choose to store them in the refrigerator, keep them in a crisper with low humidity and keep them out of plastic bags which can trap moisture.
  • Dark. Changing light conditions cause fluctuations in temperature and humidity, both things that onions do not enjoy. Keep them in a dark place away from direct sunlight.
  • Ventilated.  Keep onions in a mesh bag or in a single layer to ensure air can get at them. DO NOT store in plastic bags.  You could even store them in old pantyhose – insert one onion, twist the pantyhose, insert next onion, repeat.  Hang in a dark, cool place or lay on the cool floor.
  • Isolated.  Onions do off-gas and will affect the flavor of food around them, it’s best they have their own space. Not only do they give off gas, but they are easily impacted by the gas put off by other vegetables like potatoes. This causes them to sprout prematurely, so be sure to store onions and potatoes separately.
Mesh bags help ensure good air circulation. Old nylons work well too!

How Long Will Onions Last

Properly cured onions, when stored as indicated above, can last two to three months, sometimes longer.

If you absolutely have no choice but to store them in the fridge or at room temperature, only buy as many onions as you can use in a week or two.

At room temperature, expect whole onions to last one to two weeks before they start sprouting or becoming soft. They’re still safe to eat, but they may start tasting a little off (sometimes more pungent).

In the fridge, you risk getting mouldy or rotten onions because of moisture build up. Expect whole onions to last one to two weeks if kept in the fridge.

Other types of onions like leeks or green onions, can be wrapped in a paper towel in a plastic bag and kept in the fridge for several weeks.  

Timing Matters for Onion Storage

The time of year makes a difference. Here in North America, local onions are harvested in the late summer and fall. Our farmers are really good about properly curing and storing them and we can often buy local onions in winter and spring. But by the time March hits, those onions are on their last legs. Expect onions in spring to have a shorter shelf life than when you buy those same onions in fall or winter.

This causes me to buy onions differently. In the fall, I’ll buy bigger bags, knowing they’ll last longer. In late spring, I buy only as many onions as I need for the week ahead.

Sprouting onions are safe to eat, they just won’t store as long.

What to Look For When Buying Onions

Pick the best, freshest onions so they last the longest. Use your senses to pick the best onions – look, smell and feel.

Look for any signs of damage, brown spots or sprouting. A blemish free onion will store much longer.

Feel for firm onions with dry, papery skins. Avoid soft onions.

Smell the onions. Fresh, firm onions should have a mild onion scent. If you smell a strong flavour when you pick up a bag of onions, it may not be the freshest.

Remember, if you happen to have an onion that has a bruise or sprout, it’s perfectly fine to eat. Just use that onion before the ones that don’t.

How to Store Cut or Peeled Onions

Once you peel, chop, dice, cut or otherwise expose onions to air, you need to store them differently. This is when you want to store them in the refrigerator.

Wrap peeled, partially cut or diced onions very well to prevent odors. They should last in your fridge for up to 10 days.

If you don’t think you’ll use them by then, consider putting them in the freezer.

What if You Don’t Have Cool Storage Space

If you’ve got a cold room you’re set – simply hang your onions in a mesh bag or keep them in a crate, basket or mesh bag on the floor and you’ll have fresh onions whenever you need them. To prevent spoilage, don’t overfill your mesh bags. Use more bags with smaller amounts rather than stuff only one bag. Imagine that even the onions in the very middle of the bag need air circulation too.

Our house is well insulated and we don’t have a cold storage room. We are limited to the amount of cool/dark/dry space we have in our house. And, our garage is not insulated and goes well below freezing, so that’s not an option for us either. If you’re in the same situation, consider preserving onions. For example, did you know you can cut onions and keep them in the freezer? Read on…

Processing onions may be another good strategy. I use the food processor when freezing or dehydrating onions.

Oh, making this delicious French Onion Soup is another tasty strategy for using up extra onions!

Onion Preserving Videos

Video: Storing & Preserving Onions

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Video: Freezing Onions

or Read the Full article on Freezing Onions.

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Video: Dehydrating Onions

or Read the full article on Dehydrating Onions.

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What If there is Black Mould on My Onions

The USDA says black mould on onion is caused by aspergillus niger, a common fungus in soil. They recommend rinsing off small amounts of the black mould on the outer scales of the onion under cool, running tap water or cut off the affected layers. The unaffected part can be used. Persons known to be allergic to Aspergillus niger should not use onions with black mould.

More Reading

What’s your preferred way to manage a big haul of onions? Freeze, dry or store them well? Let me know in the comments or on Instagram @GetGettyS or on Facebook @GettyStewart.HomeEconomist.

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