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How To Store Onions

Whether you’re a home gardener who loves to cook or a home chef who often buys fresh produce, sometimes it’s hard to use up all of your vegetables before they go bad.

If you struggle with having too much produce, food storage can become one of your best friends. For onions, specifically, there are many ways to store them and keep them fresh so you never have to worry about spoilage again.

Keep reading to learn all about how to store onions and what you can do to extend their lifespan.

how to store onions

How to Store Whole Onions

If you’re wondering how to store fresh, whole onions, look no further. Uncut onions can last up to three months when stored properly.

Keep onions in a dark place with cool temperatures (between 45 and 55 degrees Fahrenheit). This can be a cool pantry, basement, or even your garage, so long as it doesn’t get too hot. Be aware that moisture and humidity are not good for onion, so don’t store them in the refrigerator.

If you’re struggling to find a way to keep your onions temperature controlled, but still need to know how to store onions, you’re in luck. Whole onions can last for up to four weeks at room temperature.

To get the most life out of your onions, be sure they have proper ventilation to prevent molding in storage. When storing onions, keep in mind that they are prone to moisture absorption, which can result in quick spoiling and cause them to be mushy.

One great way to maintain good ventilation is by storing your onions in an open basket or loose paper bag. Don’t store onions in a plastic bag (like the ones from the grocery or market). Plastic bags don’t breathe and increase an onion’s chance for rotting.

Lastly, don’t store your onions near other moisture-releasing foods. Specifically, fruits, potatoes, and lettuces increase humidity and decrease ventilation which can cause premature rotting. So store your onions far away from these foods.

How to Store Used Onions

Chopped red onion on a wooden cutting board

Peeled Onions

Unlike whole onions, the best way to store onions that have been peeled is actually in the refrigerator where they can last for up to two weeks. The fridge also protects your exposed vegetable from contamination by germs and other bacteria that contribute to rotting and are harmful to ingest.

Another technique for how to store peeled onions is by placing them in a bowl of cold water. This method will keep your onions fresh and moist, and also helps contain the smell.

Sliced or Diced Onions

Diced onions are prone to browning quickly, so here are a few of our favorite tips on how to store onions even after they’ve been cut:

Diced onions will keep in the refrigerator for up to 10 days. All you have to do is put them in a resealable, airtight bag or wrap them in plastic wrap. If you buy diced onions pre-cut, they usually come in containers that are perfect for preserving freshness if you keep them refrigerated.

You can also store onions in the freezer to preserve freshness for up to six months. Frozen onions make the perfect ingredient for flavoring soups, casseroles, and other baked veggie dishes. For more information on this, make sure to check out our post all about how to store onions in the freezer.

Cooked onions

If there’s any time to take caution when storing your onions, it’s after they’ve been cooked. Cooked onions, like chopped and peeled, should be stored in the fridge. Improper storage can lead to the growth of toxic bacteria, like E. coli, which can make you sick if eaten.

If you have leftovers from cooking, you can put your onions in a sealed airtight container and leave them in the refrigerator for up to five days. When you’re ready to use them, you can reheat these onions in the microwave or on the stove.

How to Store Leeks and Spring Onions

Raw Green Organic Leeks Ready to Chop

Listed above are some tips on how to store onions you typically consider, like white, yellow, or red. So, now you may be wondering how to store leeks, green onions, and other unique onions of that nature.

Storing these vegetables is a simple process and keeps them fresh for two to three weeks. All you need to do is place your onion stalks in a damp paper towel (emphasis on the word damp).

Then, put the towel-wrapped stalks in a plastic bag, seal it up, and place in the fridge. If the paper towel dries out at all, you can periodically re-dampen it to maintain moisture

How to Know When Onions Are Bad

Sometimes, despite your best efforts at storage, you’re left with some questionable and potentially over-ripe vegetables. One way to know if your onion has started to go bad is if it develops dark spots. Eventually, these spots will grow mold and should be thrown away to avoid any chance of getting sick.

Onions that are going bad may also start sprouting, which is another indication that it’s time to be thrown away.

You can also feel your onion to know if it has gone bad. If the vegetable is mushy, has any soft spots, or feels slimy, now is the time to get rid of it.

Lastly, onions that have a strong, ammonia-like stench that’s smelling up your kitchen is a pretty good indication that this veggie is past its time.

Frequently Asked Questions

Whole red onions, sometimes called Bombay or Bermuda onions

Which type of onions last the longest?

Everyone knows about yellow, orange, and red onions, but did you know each of these types have subcategories that can play a role in their storage abilities? Overall, the best onions for storage are yellow onions. To be more specific, Copra, Sweet Sandwich, and Yellow Stuttgarter onions will last the longest when stored appropriately.

As for red onions, the Red Zeppelin variety is second to those listed above and is one of the best onion types for storage, as well.

On the opposite end, there are quite a few types of onions that are less than ideal for long-term storage. There are onions that are grown specifically for short-term storage. They include Walla Walla (sweet) onions, Candy onions, and Sweet Spanish onions.

Generally, a good rule of thumb when deciding which onions are best for long-term storage is first to determine whether they’re hybrid or non-hybrid varieties. Typically, hybrid varieties are made for storage and are your best bet for long-term freshness.

Can I store different onion types together?

The short answer is yes, you can store onions of different varieties together. However, make sure to follow all the tips outlined above to determine how to store onions throughout their different phases of processing to maintain optimum freshness.

How else can I use my leftover onion?

If you’ve stored your onions for as long as you can but still have plenty of leftovers, there are some great recipes out there to help you use up the rest of this veggie. With such a unique and complex flavor, using up leftover onions is a great way to get creative in the kitchen while also reducing food waste.

If you’re normally a sweet breakfast lover and are looking to try new things, check out this Savory Apple Onion Tart Recipe. It’s a great way to use stored onions and is sure to impress any guest. You’ll need your leftover yellow onion, an apple, some cheese, mustard, a pie crust, and a few other ingredients that make this dish come to life.

Another great way to preserve any leftover red onion you have is by pickling them. Pickled red onions can last for up to three weeks in the brine, and are perfect for salads, avocado toasts, and much more. To learn how to store onions by pickling, take a look at this quick and easy recipe.

For those with plenty of leftover green onions, there are tons of ways to incorporate these veggies into your favorite dish. It can be added as a flavor boost to sauteed vegetables, blended in your go-to salad dressing, or the as the perfect garnish to a delicious spinach dip.

Now That You Know

Food waste is a big concern for many people, especially with grocery prices that seem to keep going up. Hopefully, now you know a bit more about all of the different ways to store onions and preserve their freshness.

Whether you’re an avid home chef or simply hate throwing away food, these tips can help you get the most out of not only your onions but also your time and money.

For more information, check out our onions post. Here you’ll find information on different types of onions, onion recipes, how to grow your own, and so much more!