How to Store Onions Long Term

How to store onions long term requires understanding the allium family better. Once you understand this layered bulb veggie, you’ll never have to deal with bad onions again.

Yellow, white, sweet onions, and red onions have a long shelf life when stored in cool, dry, well ventilated, dark spaces. Use your pantry, dry basement, and cool garage for good storage spaces with proper air circulation.

Bottom line: Moisture is the enemy when it comes to their long life. Never wash onions before storing them, because that would increase moisture, and make them more perishable. In fact, when you buy store cut onions, they’ve been sitting out in dry, 75 degree heat as their curing process. That’s how their outer layers dry out so nicely.

The more potent onions, like yellow onions are recommended for storing the longest.

1. Keep Onions and Potatoes Separate

Keep potatoes and onions in a cool, dark, dry, ventilated space at room temperature. Since onions give off gasses like ethylene, which causes potatoes to sprout faster, they should not be in the same container.

Try Mesh bags you can hang, hide them in the pantry with aerated canisters, or, tie a knot and string your onions for the ‘gram.

2. Store Whole Onions Out Of The Refrigerator When Possible

Onions and garlic should not be refrigerated because they absorb moisture and can spoil more quickly there.

After you cut onions (cut off soft spots), they’re best stored in an airtight container. These special containers help keep your sliced onions fresh and the odor contained.  I like this one best (other containers were hard to open and close, have odor problems, aren’t BPA free, etc.). Just make sure you lock it properly so the odors don’t leak out.

Moisture will build in the fridge, so don’t wait too long to use your partially cut onions. You also don’t want to use plastic bags, because these will encourage more moisture too. Try adding a dry paper towel to the onion container to soak up any moisture that could spoil the produce. This helps since they are bulbs; when cut, we are removing the outer papery covering that protects the moisture balance.

The exception to this rule the green onion (also known as spring onions or scallions) because they’re soft. Proper storage would be to keep these babies in the fridge.

3. Consider Canning

As an alternative to keeping raw onions around, they can be blanched or pickled for wonderful canning options.

I’m obsessed with caramelized onion jam and candied jalapeño jam. For a healthier option, choose a different oil than the recipe suggests. I prefer using unrefined avocado oil, which has a high smoke point.

Caramelized onions are a great addition to any bruschetta. If you have a lot of onions, dice them, put them in jars, or freeze in airtight containers or wraps. Cooked onions last a very long time when canned.

4. Make Broth or Compost

Don’t forget to save the bits, ends and pieces you cut off. Store them in the refrigerator or freezer to make your own delicious, low-sodium veggie broth.

Or start a compost bucket. I prefer using this bucket so I can throw it in the dishwasher to keep it clean. BONUS: it looks pretty on the counter.

5. Meal Prep: Freeze for efficiency

Chopping and dicing onions, scallions, leeks, garlic, and shallots with other vegetables are good ideas for long term storage. Try mixing with peppers, celery and carrots for your own signature blend.

Bag and freeze into ice cube trays to save a lot of meal prep time. Just blanch them for 1 or 2 minutes before storing.

I make Soffritto (Italian) or Mirepoix (French) for almost everything—bolognese, stews, fish, soups. Having veggies chopped, portioned and frozen gives me more motivation to serve up these things than facing all that chopping at the end of a busy day.

6. Other Alliums 

Onions in the fridge: Green onions, leeks, and shallots do well in the refrigerator for days. And, again, rather than letting them spoil, they too can be cut into slices, chopped, portioned, and put into the freezer.

7. Growing Onions and other Alliums

These bulb veggies are easy to grow in your garden. So if your onions are getting older, this may be the time to plant the sprouted bulb. You can eat the sprouted onions or garlic, and, in fact, there is more protein in the sprouts.

Peeled onions will reveal sprouts in the center. Just make sure you DO NOT cut or slice the onion until you’ve removed the center sprouts, like detailed here. My store bought onions started sprouting in about a month.

The planting season for onions is earlier than other vegetables. Typically these are planted in March in climates that have hot summers. Since I’m in California, I plant these year round whenever my store-bought onions sprout. Expect to have onions in about 90 days.

Alliums are revered by many cultures for their health benefit. They are thought to lower cholesterol, blood pressure, and even have properties that are cancer and cardiovascular disease preventives. It’s always good to know that onions offer wonderful health benefits that make long term storage worth it.

National Onion Day is in June. Tag #thevanillaplum with your fun storage tips.