Curing and Storing Onions for 10 months or more!

22 Mar.,2023


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Curing and storing onions for 10 months or more isn’t as hard as you might think!  Choose the right variety and follow these steps and you can have your garden-grown onions for 10 months or more!

Onions are an indispensable garden crop for our kitchen. Curing and storing onions correctly will assure you have this garden goody available all year long! Yep, that’s right! If you grow the right onion and then cure and store it correctly you can get your onions to last up to 10 months.

Here’s proof we are curing and storing onions for 10 months or more. These are our last two Copra onions. They are looking a little ragged but are still usable. The two onions at the top are freshly harvested.

This picture was taken on August 15th, the same day we harvested our first onions for the year! But even in years where they don’t last till the next harvest, they can still last well into the summer when you will have green onions to harvest. Because of this, it has been years since we’ve bought an onion!!

So how can you begin curing and storing onions to last up to 12 months? Following my 4 easy steps will help you get your homegrown onions to last a whole lot longer.

1. Choosing the right onion

There are two types of onions, mild and pungent.
Mild onions are usually larger and sweeter. They are often used raw and are perfect on salads, burgers, and even onion rings. But mild onions are not good “storers” and usually only last a couple of months in storage. Examples of mild onions include Spanish, Bermuda, and Vidalid.

Pungent onions are always smaller and are usually used for cooking. The same strong-smelling compound that makes your eyes water when you cut them is responsible for pungent onion’s long storage capacity. Pungent onion varieties include Copra, Candy, Patterson, Superstar, and Red Tropea.

So if you want to have long storing onions grow pungent varieties. My suggestion is Copra! We love Copra onions and they are the longest storing onion I know of! Copras are advertised to last 10 months or more and they live up to the advertising! If stored correctly we have had them last a year.

Recently I have found it is becoming harder to find Copra onions. Fewer growers are producing them so you may have to grow them yourself from seed. I have learned that the variety Patterson is a good replacement for Copra and will last just as long in storage.

We love to plant our onions using seedlings, and our favorite place to buy those seedlings is Dixondale Farms, they are based in Texas but sell all over the US and Canada. We have always been please with the seedlings we get from Dixondale!

2. Harvest at the right time

The next step in curing and storing onions is harvesting.  As mid-summer approaches your onions will start to “bulb” up. When the tops start to flop over that indicates the onions have finished growing and are moving into their final maturing stage. Once the tops start to yellow and wither you should stop watering the plants for a week. For a little more detailed discussion of how to harvest onions, you can check out this article I wrote on the topic.

3. Cure your onions for at least 3 weeks

Now here’s the key. Let your onions sit and dry for at least 3 weeks and up to 4 weeks! Patience and a nice airy spot are the keys! You know your onions are cured when the necks (where the tops attach to the bulb) are dry and tight and the outer layers of skin are dry, papery, and rustling and the tops have withered and dried completely.

On a dry sunny day dig up the bulbs (be sure to dig them out, do not pull them out by the tops as this can damage the bulbs). If there is no chance of rain or frost you can leave your onions lying in the garden to dry for a day or two. Otherwise, bring the bulbs into a protected area like a covered porch or garage. I place all my onions on a screen I built just for this purpose in my garage. You then simply let your onions sit and dry for 3 or 4 weeks.

Once your onions are cured trim off the roots with a pair of scissors and brush off any dirt. You can remove the top one or two layers of dried skin to give you a nice clean-looking onion. If you are planning on braiding your onions or tying them to a string then leave the tops on. If not then you should cut the tops off to about 1 inch. This is a good chance to see if the tops have really dried. If there is still moisture in the tops then you should not store that onion, put it in the fridge and use it up soon.

Now go through all your onions and remove any that have bruises damage or rot. Again use these up quickly. I also like to sort my onions by size. Over the years I have found that smaller onions store the longest. So I put the smaller onions in one bag and the larger in another and use the larger ones first!

4. Store in a cold, dry, dark place

We like to store our onions in a mesh bag and most of the year they hang on a nail in our garage. Keeping them out of direct light or even better in the dark also helps them last longer.

Onions should be stored in temperatures between 35 and 50 degrees Fahrenheit (2 to 10 Celsius). The optimal storage is 35 to 40. But be sure to protect them from freezing, if they freeze and then thaw they will start to rot.

If you only have a few onions a fridge isn’t a bad option. But if you have 50 or more then you need to find a cool spot. In the winter our garage is perfect, but it is too hot in the fall and spring.  We end up putting them in a cool dark room in the basement for the fall.  Then we put them in the garage all winter.   When there are any left in the spring we put them in the fridge till they are gone.

If your onions start growing roots, then where you are storing them is too humid. If the onions start to sprout then it is too warm. In either case, you need to use up the onions quickly or you could chop them up and put them in the freezer. Just be sure to double bag them so the smell and flavor of the onions doesn’t spread to the other foods in your freezer!

By following these simple steps you can easily get pungent varieties of onions to last 10 or more months filling your cooking with tons of homegrown flavor all year long!!!  If you would like to learn more about growing onions you can check out my complete growing guide for onions.

If you have any questions on onion cold storage. We will give the professional answers to your questions.