How Long Do Onions Last | Best Onion Storage Tips

Last updated: 10/31/21

Onions are a root vegetable that does not last forever.  It still begs the question of how long do onions last.

Onions’ shelf life is contingent on the many ways & methods that you choose to store it. 

• Freshly harvested onions will last for 1-2 months in the fridge.
• Properly stored onions will last 2-3 months at room temperature.  
• Cooked onions will last for approximately 7-9 days in the fridge.
• Frozen onions will last for 2-12 months in the freezer.  
• Pickled onions lasts for about 4-6 months if pickled, canned, and stored in a refrigerator properly.

You will learn about the shelf life of onions, plus some tips on how to make onions last longer.

There is more to just sticking onions in your food pantry.  You will learn the many different ways to extend onion’s shelf life.  Our suggestions are based on the premise that you properly follow the practices of food preservation.

As always, use your best judgment when trying to determine when something is no longer edible or safe to eat.

1 – Shelf Life of Onions at Room Temperature

Like garlic, onions can remain in good condition for up to 2 to 3 months at room temperature.

There’s wisdom in choosing these types of storage spaces because onions readily absorb moisture and if temperature or humidity rise, onions either sprout or rot.

So the right temperature, humidity and ventilation are critical conditions for ensuring the longevity of your onions but a host of other conditions also play apart in best practices for keeping your onions fresh.

Many factors dovetail together when plans are being made for storing onions because it’s not only a matter of buying and storing them somewhere and leaving them there

Many factors are involved and in this article we will explore the different ways on how to prolong the freshness of your onions.

2- How Long Do Onions Last in the Fridge | Shelf Life of Onions in the Fridge

Onions last approximately 1-2 months if stored as a whole bulb when in a compartment of your fridge. Onions last after cut for approximately 7-10 days.

This is also true for most bulb onions such as white, yellow or red onions.

People are usually inclined to leave leftovers of cooked food in the refrigerator or freezer to make them last longer..

However, treating they fail to realize that treating vegetables in the same way poses certain problems.

For instance, they may decide to chop up a couple of onions and leave them in the fridge completely convinced that they would stay fresh until they are ready to be used.

They often fail to think about for how long the chopped onions would actually stay fresh.  They last about 7-10 days after they are chopped. This is critical information for you and me to know.

A plastic container that can be resealed is best for keeping the onion good and fresh but if you can’t find a container, tightly wrapping the onions with plastic wrap or aluminum foil will do just fine.

3- Shelf Life of Onions in the Freezer

Frozen onions will last for 2 – 12 months in the freezer depending on your preparation techniques.

This means you should place the onions in a container or plastic bag before putting them in the freezer you have in  your home.

This will help prolong the freshness of your onions.

It’s generally the case that when chopped onions are freezer frozen, they are usually of a softer texture than those you put inside the refrigerator once they thaw and shed their ice coating.

These conditions are the result of the intensity of the cold generated by the freezer which transforms the chopped onions into perfect ingredients for any dish you might want to cook up and impress your visitors or your own folks.

It’s imperative however that you place the cooked onions as soon as you can in airtight containers or if  unavailable, a resealable bag, several hours after cooking them.

When your store your cooked onions in the fridge after placing them in suitable containers they will remain in good condition for three to five days.

If you want your onions to last longer, especially if you are thinking of traveling abroad, you should definitely store the prepared onions in the freezer. In doing so, you onions would stay fresh for up to three months.

5- How to Properly Store Onions | Best Ways to Store Onions

The storing process is critical when it comes to prolonging the freshness and usability of your onions. 

We’ve already covered how to store cooked onions so we’ll look at other forms of onions and the dependable ways of storing them so they can stay fresh for the longest time possible.

Raw Onions

• Onions destined for storage in room temperature must be free from imperfections such as skin damage, dirt, sprouts, thin skin or softness.
• The perfect place for storing newly purchased onions would be in a cool, dry and dark place such as the basement, pantry or even the garage where ventilation is good.
• It would be a good idea to have a thermometer placed in the storage space to make sure the room temperature hovers between 40-50°F
• While picking the ideal place for storing your onions is important, preparations beforehand are essential.

Remember not to store vegetables in the same place, especially onions with potatoes. Why?

Because these veggies emit gases that trigger ripening mechanisms in both of them making them vulnerable to rotting.

It’s equally unwise to put whole or halved raw onions in the refrigerator or freezer as they tend to become soggy and soft making them difficult to handle during the cooking process.

There are several highly effective storage methods that can be applied to onions during separate stages of processing that deprive onions of their skin cover.

Peeled Onions

Very soon after an onion is peeled it should be stored in the fridge the prevent bacteria for setting in.

Again, the use of airtight containers is recommended when you are preparing to store your onions in the fridge and you should make sure the temperature is set to 40°F or 4°C.

The Department of Agriculture has confirmed that if these steps are strictly followed, peeled onions will stay fresh from up to 10 – 14 days in the fridge.

Sliced, Cut or Diced Onions

The method of storing chopped onions has been discussed in detail in the above sections, especially the need to place them in suitable containers and the right temperatures.

The same applies to sliced, cut or diced onions.

With the right storage preparations, sliced, cut or diced onions can be stored in the fridge for up to 20 days.

Of course you can purchase already sliced onions from local supermarkets  or grocery store but you need to make sure you immediately store them in your fridge and discard them when they expire.

If you really want a steady supply of sliced, cut or diced onions for your soups, casseroles and stews, you can decide to store them in the freezer where they will remain in top shape for three to six months.

Cooked Onions

As already discussed above, the storing of cooked onions is a must to keep them fresh and usable for up to three to five days.

 Again, the need to prepare the cooked onions for storing several hours after cooking  is vital for maintaining the goodness trapped in your cooked onions.

The danger is that if the cooked onions are left unattended after being cooked, bacteria will find its way into them.

Pickled Onions

Another highly effective method of extending the shelf life of your onions is pickling them.

This involves preventing the growth of bacteria by using special solutions and enable onions to remain edible for up to six months.

6- How to Know if Onions are Bad or Spoiled

Like all vegetables onions will go bad over time. It is important that you are able to tell when their quality starts to deteriorate.

There are three ways that show your onions are going bad.

Look – the appearance of black spots on the onions is a sure sign that mold has begun its work.

Soon, young shoots will start to appear at the top part of the onion bulb. 

The appearance of thin white strands on sliced onion halves is another sign that mold is playing up and your onions are no longer safe to use.

Feel – smoothness and firmness are sure signs of onion health while the appearance of soft spots signals that deterioration has set in. Chopped or sliced onion halves are going bad if a slimy texture appear on them.

Smell – onions that smell bad or just don’t smell like onions is a sure sign your onions are rotting. 

However, you now know “How Long Do Onions Last” and the techniques to make sure none of your onions to go bad.

7- Methods to Make Onions Last

Onions can be stored for a good period of time if you prepare it properly. Let’s take a look at a few different ways on preserving onions.  

Freezing Your Onions

The best way to make onions last is by freezing chopped or cut onions.  There are some steps you need to complete before you freeze them:

1. Blanch, or boil the onions in boiling water for approximately 3 minutes.
2. Remove from the boiling water after 3 minutes and submerge in a cold ice bath.  This stops the cooking process.
3. Drain the onions and pat dry as best as possible.
4. Place dried onions and pieces on a tray lined with parchment paper.
5. Place in the freezer for approximately 45 minutes to an hour.  This will ensure that the onions freezes but does not clump together.
6. Place frozen onions in a tightly sealed bag.  Vacuum sealed bags are the most optimal way.

Pickling Onions

This method of preserving onions involves placing the onions is a pickling liquid.  Pickling is almost always a liquid that is composed of vinegar and salt. It also can include some other spices that lend well to the pickling flavors that you are most familiar with.

Typically, pickled onions will last about 6 months in the fridge.  The combination of vinegar and salt provides a very acidic environment that impedes bacteria.  You definitely still want to keep it covered and stored in the fridge.

Canning Onions

There are 2 methods of canning that we must discuss.  There is the water bath canning method and there is pressure cooking canning. 

Onions require the pressure cooking canning method.

Pressure cooking canning methods will ensure that the temperature onions are processed or boiled in is well above the temperature to kill off any bacterial spores that can cause botulism. 

The temperature in a pressure cooker is 250°F or more.

Water bath canning will never reach this temperature is not recommended to process onions.  Botulism spores can actually survive normal boiling temperatures so are not quite killed off using this method.

The best guide that we use for canning and pickling is the Ball Complete Book of Home Preserving.  

You can find this book here.

Other Methods To Make Onions Last

You can also dehydrate onions and make it into a powder.  This can be used in many cooking dishes. 

You would need to use some type of food dehydrator it and process the onions at 145°F until crisp.

Dehydrating basically dries the onions of 90-95% of its water content.  This slows down the rate at which onions spoils.

You still need to store it in an airtight container to maximize its shelf life.

More Info

Keep in mind that the information that we provided is based on recommendations from the FDA, our own observations, and the data from other sources such as the Ball guide we mentioned above.

Please do your own due diligence in determining your own set of guidelines.

This information provided is at your own risk.  Use your best judgment.  We did our best to present you with the best information we had available at the time of this writing.

The shelf lifetimes are based on the following conditions of your storage area:

• Room temperature of 60°- 70°F
• Refrigerator temperature of 35° – 40° F
• Freezer temperature of 0°F or lower.

Check out our guide on ways of preserving food for more information on some of the techniques.

Related Questions

• How long do green onions last in the fridge? – Green onions will last anywhere from 2 weeks to 5 weeks in the refrigerator depending on your storage method
• How long do uncut onions last in the fridge? – Uncut onions will last approximately 7-10 days if stored properly in the fridge.