How Long Do Onions Last? [Sliced vs Whole]

Onions are some of the most commonly purchased items from the produce section.

Almost anything savory you cook will call for onion, plus onions are great toppings for sandwiches, burgers, hot dogs, and more. So, how long do these roots last once you bring them home from the supermarket? 

Whole onions will last several months (some say up to a year) if stored correctly. Still, you should expect your whole, fresh onion to keep for several weeks minimum on your counter or in the pantry. Cut or sliced onions typically last up to one week stored in the fridge or months in the freezer. 

Do Onions Go Bad?

Onions, like any other food item, will eventually go bad. Onions can start to rot, spoil, grow mold, or grow sprouts.

However, this typically doesn’t happen for a while. Onions have a pretty long shelf life and can last months when stored correctly. 

However, once you cut an onion, it will start to break down and go bad much quicker. This is because onions have several protective layers to keep the moisture in and bacteria out.

Plus, the acid content helps reduce bacteria growth which slows down how quickly they go bad. 

So, once you cut through the onion and break through the outer layers, you should use it within the next few days. 

How Long Do Onions Last on the Counter?

Fresh, whole onions will last several weeks (possibly up to a couple of months) stored at room temperature on your counter.

Onions

The ideal location for storing onions is in a dark, cool environment where the temperature is between 35° F and 55° F

That’s why root cellars exist. These dark, cool locations were designed to extend the life of root vegetables like onions, potatoes, and garlic.

Still, most of us don’t have a root cellar at home, so storing onions in the kitchen is our only option. 

To extend the shelf life, keep your onions in a bowl or basket on your counter. You don’t want to restrict airflow by storing onions in a plastic bag or other sealed container.

You also want to keep them out of direct sunlight. Darker is better for these roots. 

Another way to extend your onion’s life is by storing it away from other food items that may release moisture.

Some people throw onions into a basket with garlic and potatoes for storage, but this will actually shorten the shelf life when the gasses released by each item interact with one another. 

How Long Do Onions Last in the Fridge?

Whole, uncut onions will last up to two months in the fridge. However, you should be aware that storing these roots in the fridge may affect their texture and quality.

In some cases, they may even start to spoil faster than if you left them on your counter.

At the very least, they will become soft and spongy, losing their fresh, crispy texture. 

However, once you cut or slice onions, they should always be stored in the fridge. These will stay good for 7-10 days as long as you keep them in a sealed, airtight container or zip-top bag.

Onions that you’ve already cooked should also be stored in the fridge. These will keep for a few days if you store them in an airtight container.    

How Long Do Onions Last in the Pantry?

Fresh, whole onions will last two to three months (on average) as long as they’re kept in a cool, dry, dark place.

Your pantry might be a great spot if it meets those criteria. Still, most homes aren’t quite cool enough to maximize an onion’s shelf life.

In any case, onions stored at room temperature typically last several weeks, up to a month or two. 

If you keep your onions in the pantry, be sure they have good ventilation. If you put them into a plastic bag at the supermarket, be sure to remove them from the bag when you get home. Poor air circulation will cause them to break down faster. 

It’s also a good idea to keep them separate from other root veggies. So, maybe place your bag of potatoes on a different shelf in the pantry away from your onions to maximize the lifespan of both items. 

How Long Do Onions Last in the Freezer?

You can extend your onions’ shelf life significantly by storing them in the freezer, but you’ll need to cut them up first.

Fresh, whole onions shouldn’t be stored in the freezer. Chopped or sliced onions will last up to eight months in the freezer. 

To freeze raw onions, you should peel them, slice, chop, or dice them however you’d like.

Then, store them in an airtight plastic container or freezer bag and place them in the freezer. Be sure to date the package so you know how long they’ve been in there. 

For cooked onions, you can follow the same process. These will stay good in the freezer for up to one year if sealed in an airtight bag or container.

How Long Do Red Onions Last?

Red onions have the same shelf life as yellow or white onions. That means they’ll stay usually good for four to six weeks at room temperature.

Red Onions

Whether you store them on your counter or in the pantry, you can maximize the shelf life by keeping them as cool as possible and ensuring there’s good air circulation. 

That means you shouldn’t store your whole red onions in a plastic bag or sealed container.

You should also keep your red onions separate from other onions, potatoes, and garlic. Having them near each other can make them start breaking down faster. 

Like other onions, you should store red onions in the fridge or freezer once you cut them up. They can last about a week in the fridge and several months in the freezer if stored properly. 

How to Preserve Onions for Months

To safely store your onions for several months, you should store them in a cool, dark, dry location.

If you can keep them somewhere dry at temperatures between 35° F and 55° F, your onions may last up to a year. 

So, if you have a cellar or basement that’s nice and cool, or even a chilly garage, it could be an ideal spot to store your onions. 

Now, you may be thinking about your refrigerator – it’s cold and dark in there! Onions are highly susceptible to moist locations and they will absorb any moisture and humidity in the air.

For that reason, storing onions in the fridge will often cause them to start breaking down faster than if you leave them at room temperature. At the very least, it will affect the onion’s quality and texture. 

However, it’s possible to keep onions in the fridge and extend their shelf life if you can store them in a way to prevent excess moisture.

For example, you can wrap each onion in paper towels to help absorb moisture and place them in a humidity-controlled bin if your fridge has that feature. 

How Can You Tell If an Onion is Bad?

Even though onions can last quite a while once you get them home, they’ll still start to go bad eventually. You can tell if an onion is bad based on its appearance, texture and firmness, and odor. 

Here are some signs to look for: 

Dark Spots

If you notice discoloration on the onion’s exterior, it could indicate a bad spot on the inside. Dark or brown spots usually mean that the onion is starting to spoil inside, especially if the spot is soft to the touch.

Sometimes, you may not see a brown spot until you cut into the onion. Brown spots on the inside mean you should throw the onion away.

Mold or Sprouts

If you notice visible mold on the onion’s skin or exterior, throw it out. Onions that are starting to sprout also mean that the onion is old and may be bad. In some cases, you can cut away the sprout, but always check the inside before eating or using it. 

Texture and Firmness

Onions should feel firm to the touch with a fresh, crispy texture. If the onion is soft or squishy, that means it’s starting to break down inside. Similarly, if the texture is overly dry and dehydrated, it could mean the onion is bad. 

Foul Odor

Onions should smell, well, like onions. If you cut into it and notice a foul, rotting, or sour odor, throw it away. Your nose is a powerful tool when it comes to food, so if something smells “off,” it’s best to be safe than sorry. 

The Bottom Line

Onions are staple items in the kitchen. Many people buy them in bulk and keep them on hand for whenever they’re needed.

You can store onions for several weeks in your home either on the counter or in the pantry.

Avoid keeping whole onions in the fridge, but after you cut them up, they do need to go into the fridge or freezer. 

Remember, the key for extending the shelf life of an onion is finding a spot that’s cool, dry, and dark. Good airflow is important, and never store onions with potatoes or garlic.

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