How to Dehydrate Onions

So you want to know how to dehydrate onions? You're in the right place — but fair warning: it's not for the faint of nose!

While dehydrated onions are a must-have for soups, stews, and DIY onion powder, the smell during drying can be intense. This guide shows you exactly how to prep, dry, and store onions without stinking up your house — and without risking your pets’ sensitive systems.

Onions in a pile

Dehydrating onions can be a tearful job, so please run your range hood vent (if you have one) and place your dehydrator as close to the vent hood as possible.

Doing so will help enormously to take the onion odor out of the kitchen and away from your pets' sensitive noses and nervous systems— onion aroma is poisonous to them!

Onion Nutrition Info.

VITAMINS: Vitamin A, followed by Vitamin C. There are trace amounts of Niacin, Pantothenic Acid, vitamin B6, Riboflavin, and Thiamine.

MINERALS: Potassium, followed by Phosphorus, and Calcium. There are trace amounts of Iron, Zinc, Manganese, Copper, and Selenium too.

Onions also contain Omega-3 and Omega-6 fatty acids.

Air Ventilation Warning
How to Keep Your Kitchen (and Pets)
Safe from Onion Odor

You may also wish to have your windows OPEN or put the A/C on
while you're dehydrating onions or garlic... as the powerful odor
can certainly circulate throughout the entire house!

If you ABSOLUTELY LOVE onions and garlic,
it's not such a bad thing, but if you don't...
just sayin'!

Air Ventilation
Warning
How to Keep Your Kitchen
(and Pets) Safe from Onion Odor

You may also wish to have your
windows OPEN or put the A/C on
while you're dehydrating onions or
garlic... as the powerful odor
can certainly circulate throughout
the entire house!

If you ABSOLUTELY LOVE onions
 & garlic, it's not such a bad thing,
but if you don't... just sayin'!

While onions might smell delicious to us humans, remember this:

Heed The Air Ventilation
Warning Above!

Please be careful when dehydrating onions.
Keep pets away as the onion odor is poisonous to them,
as I mentioned at the top of this page.

Heed The
Air Ventilation
Warning Above!

Please be careful when dehydrating onions. Keep pets away as the onion odor is poisonous to them, as I mentioned at the top of this page.

Step-by-Step: How to Dehydrate Onions (Fresh or Frozen)

Let's get busy learning how to dehydrate onions - fresh or frozen!

If using frozen onions, ignore step 1.

  1. Peel and slice into 3/8" slices (or rings or diced).
  2. Arrange on your food dehydrator trays. Make sure they don't overlap.
  3. Turn on your food dehydrator and set the temperature between 125°F and 135°F (or per your food dehydrator's instructions).

💡 Tip: Outside the U.S.? Most dehydrating temps here are listed in Fahrenheit — use our quick converter to see the Celsius equivalent for your machine.

  • Dehydrated onion will be leathery when fully dried.
  • Drying time: between 4-12 hours.
  • Please remember to rotate your trays for even drying.
Dehydrated white onion on a Nesco dehydrator tray

This very versatile veggie is great for tons of recipes: Soups and stews, you name it!

And you can grind onions up for use as onion powder!

When slicing and chopping up your onions, you might first want to invest in a good knife...

Cutluxe 8
Cutluxe 8" Chef Knife, Full Tang

Begin by Using a Good Sharp Knife by Cutluxe!

Check out this great chef's knife with a full tang that means the handle and blade "are one" so they can't come apart when we're slicin' and a dicin'.

I know these Cutluxe Chef knives may be a little expensive, but they do last pretty much a lifetime when you maintain their cutting edges.

As an Amazon Associate, I earn commission from qualifying purchases. The price you pay does not increase.  Read disclosure here.

...or you may wish to treat yourself to this awesome slicer like I did:

SUPMAKIN 5-in-1 Mandoline Slicer
SUPMAKIN 5-in-1 Mandoline Slicer

SUPMAKIN Slicer + Dicer Mandoline ~ OnceForAll Brand

French fry cutter, vegetable chopper, vegetable slicer cutter, potato slicer, chopper for kitchen meal prep.

A multi-function mandoline that I just couldn't resist getting!

🧄 Got Extra Tray Space? Dry Garlic While You're at It

NOTE: When dehydrating this pungent veggie, you might dehydrate some garlic at the same time if you've got a spare dehydrator tray or two available!

Don't mix the two with, say, apples, when dehydrating—unless you WANT your APPLES to taste like ONIONS or GARLIC!!

Onion rings ready to dehydrate
Dried onion rings in a bowl

Reader Tip: Drying 50 lbs of Onions (Yes, Really!)

"I noticed that my white onions did not turn as brown as my Vidalia onions, did a little research, and found that it might have to do with the sweeter onion, which makes sense.

I also noticed that the Vidalia seems sweeter dried than fresh, which is fine with me.

I am so very happy that I found a great deal on them and dried close to 50 lbs of them this spring. I did do many batches outside when I saw that the humidity was very low, starting them outside in the morning.

By night the smell was almost gone when I finished them in the home."

Which Onion Is Best for Dehydrating? Here’s the Breakdown

Here's a cool post on ten different types of onions and it shows what the best onion is to use in a specific dish.

Four varieties of onions

There are many different types of onions, but the most common type is the white onion. Other popular types of onions include the red onion, the yellow onion, and the sweet onion. Each type of onion has its own unique flavor, so be sure to try a few different kinds to find your favorite.

Onions can be stored in a cool, dry place for up to two weeks. However, if you plan on storing them for longer, they can be stored in the fridge for up to eight weeks. Be sure to keep them in a paper bag or a mesh bag so they can breathe.

Onions can be used in a variety of recipes, or they can be eaten raw.

When cooked, onions become sweeter and more mild.

So, whether you like them raw or cooked, there’s an onion out there for you!

Where and How Onions Grow Best

Onions grow best in areas with full sun and well-drained soil. They are a cold-weather crop, so they do not do well in warm or damp conditions. Additionally, onions need full sun and well-drained soil to thrive.

When to Plant Onions for a Big Harvest

Onions can be planted as soon as the ground can be worked in the spring. They are typically ready to harvest in late summer or early fall.

Thanks for taking the time to stop by and learn how to dehydrate onions. Remember to run the range vent hood, or at the very least, crank open a few windows! Keep pets away from onion odors.

Onion FAQs: From Minced to Green to Frozen

Can you dehydrate minced onions?

Absolutely. Just spread them thinly, keep the layer under ¼", and dry at 125°F for 4–7 hours. Rotate trays and check often to avoid burning.

How do you dry green onions (scallions)?

Trim, separate whites and greens, slice, and dehydrate at 125°F. Whites take 4–6 hours; greens, 2–3 hours. Store separately for best shelf life.

Can I use a food dehydrator to dry onions?

Yes! Slice onions into rings or dice them, lay them out evenly, and dry between 125°F–135°F for 4–12 hours depending on size and moisture.

Can I dehydrate frozen onions?

Definitely — no need to thaw. Just skip the peeling step and lay them directly on trays. They're often pre-blanched, so they dry quickly.

Why are onions dangerous to pets?

The strong smell can irritate your pets’ respiratory systems, and onions themselves are toxic if eaten. Always ventilate well and keep dehydrators away from curious noses!

Dehydrated onions are a pantry MVP — lightweight, shelf-stable, and full of flavor. Whether you're making your own onion powder or adding them to winter soups, you’ll love the convenience.

Don’t forget to grab your free 5 Dried Food Recipes PDF (below) for more tasty ways to use your dehydrated goodies — no tears required!

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