Should You Refrigerate Onions?

Where you store your onions depends on whether you’ve cut them or not.

Stacey Lastoe is a former senior editor for CNN Travel with an Emmy for her work. Now a freelancer, her work can be found in Allrecipes, Refinery29, American Way, The Kitchn, Fodor's, and Wine Enthusiast. Stacey lives with her husband and dog in New York.

If there’s one cooking staple that’s superior to all others, a very strong case could be made for the mighty onion. Used on sandwiches, burgers, tacos, and nachos as well as in sauces, salads, meatloaf, and more, the bulb vegetable is a workhorse.

Onions add flavor, dimension, and a nice hit of acid. They are one of three key ingredients in mirepoix, a culinary term that refers to the cooking down of carrots, celery, and onion in fat. Mirepoix is the basis for tomato sauces, soups, and rich meat dishes like Beef Bourguignon, and it really can’t be done without onions.

Typically the more basic onion varieties are put to use as foundations for sauces or other dishes, but there are so many other delicious and unique varieties of onions, from scallions to green onions, to sweet onions such as Vidalia or Maui. Ramps, green onions, and leeks are all a part of the allium family too.

With so many different types of onions, you may wonder if the storage methods differ. For example, should a red onion be stored differently than a bunch of scallions? What about onions that have been partially used? Do these halves or quarters go in the fridge until you need to call upon them again, or can those stay with the bag of onions you have in your cupboard or on your kitchen counter?

Read on for more about refrigerating onions.

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Onions should be stored in a cool, dark place. A temperature range of 45 to 55 degrees Fahrenheit is considered ideal. Whole, raw onions will keep for up to several months if stored in these conditions. Cellars, pantries, and cool garages all work for onion storage.

If you don’t have access to this particular type of storage, you can leave onions out at room temperature on your kitchen counter, though you may only get up to four weeks using this method. Just be sure to keep them in a well-ventilated container such as a mesh bag or an open basket. You'll also want to keep onions away from potatoes, which release moisture that can cause the onion to spoil more quickly.

Once you’ve cut an onion, any remaining pieces should be kept in the fridge. You’ll have about a week to use the onion before it starts to lose its freshness. If you’re left with half an onion, simply wrap it in plastic, pop it into a reusable container or an airtight plastic bag and place it in your crisper drawer.

This is also true for diced or chopped onions that you’ve prepped in advance. These will be good for up to 10 days, while cooked onions (maybe you’ve caramelized a batch to use on sandwiches or salads) will last about four days in the fridge.

Raw onion pieces and halves can also be stored in the freezer in an airtight container or wrapped well in foil for up to eight months. Cooked onions can be frozen for up to a year so long as they are wrapped and stored properly.

You should not sore onions with moisture-releasing potatoes or in an airtight plastic bag.

Spring onions, onions that have been harvested before the bulb has had a chance to swell, are a bit more fragile than adult onion varieties. Since young onions include edible tops that will turn much more quickly than a full-grown adult onion that’s just represented by the bulb piece, the care and storage of this type of onion is distinct.

Scallion varieties require a bit of different care. Because the soft green of a scallion is likely to wilt or turn color if stored with a bag of white onions in a cool, dark place, take care to handle this allium variety differently.

Wrap the scallion bunch in damp paper towels and place this in an airtight plastic bag. Store this in your crisper drawer for maximum shelf life and freshness (you can get up to a week or more with this method). Alternatively, you can store the bunch of scallions in a glass of cool water and cover the exposed parts with a plastic bag.

Leeks should also be stored in the fridge when purchased fresh. Place unwashed, untrimmed leeks (though you may need to cut the tough tops off to make them fit) in an airtight plastic bag to prevent the odor from transferring onto other foods in your crisper drawer.

Uncut onions, including Spanish, white, and red onions, will last up to three months if stored in their preferred setting of 45 to 55 degrees Fahrenheit and away from potatoes. If you store onions for longer they may sprout or get soft on the inside and will fare better in recipes where they are being cooked and not used raw.

You can eat onions that have sprouted, but be aware that the flavor may be different—more bitter—than an unsprouted onion consumed within the ideal 2 to 3 month time frame.

Cut onions will last for 7 to 10 days in the fridge if stored properly. Cooked onions will be good for about three days.

During the summer, you may find that your uncut onion’s shelf life is shorter than in colder seasons. High humidity and warm temperatures can shorten an onion’s shelf life. And it can also be more difficult to find a cool, dry place for storing onions. If you struggle with finding an area that’s the recommended 45 to 55 degrees Fahrenheit in your home, your best bet is storing your onions in the fridge while temps are high.