How to Regrow Sprouted Onion Bulbs

Cooking onions are very prone to sprouting which makes us ask, can I regrow sprouted onions? And, are they safe to eat? Find out what to do when the sprouts appear and how to prevent them in the future.

You can also grow your own ginger plant using a root from the grocery store.

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Are Sprouted Onions Safe to Eat?

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It’s very common for bulbing onions to start growing green sprouts or tops. These are onions with the papery skins that we use both raw and cooked. They need cool, dark, dry storage and it’s the warmth and/or light in our kitchens that gets them sprouting.

But does this sprouting make the onion unsafe to eat?

And is there a way to continue growing them as plants to get more onions?

The short answers are: yes, they are safe to eat. But you might not like the taste.

And yes, you can regrow them. I’ve put the instructions below.

Common Questions About Sprouted Onions

1The onions in my kitchen cupboard have sprouted. Are they safe to eat?

Yes. But. Keep reading.

2Do sprouted onions taste different than non-sprouted ones?

Yes. When bulbing onions start sprouting, the new growth gets some of its energy from the sugars within the bulb. This means the edible parts have been depleted of some of that natural sweetness we know and love, and the texture is a bit tougher.

Some people like the slightly duller flavor, others do not.

For me, it depends how far along the green growth is. If there’s just a little sprout sticking out, it means the onion will pretty much still taste fine because it hasn’t surrendered that much of its sugars yet.

If the sprouts are a few inches long or more, the main onion part is going to be super bland.

This article at Cook’s Illustrated describes their taste test: Using Sprouted Onions.

Random Cool Fact

The edible parts of bulbing onions—those layers that we can peel away—are actually modified leaves, also known as bulb scales.

3Are the sprouts growing from bulbing onions edible?

Yes. But.

Will they harm you? No.

Will you like the taste. Likely not. If you’re a hardcore onion fan, take a sample and decide for yourself.

4What’s the best way to prepare the sprouted onion for cooking?

The green sprout grows from the root of the onion, up through the middle and out the top.

The best way to salvage the onion is to cut it open, pull out the entire green shoot and roots, and use the rest.

If you want to regrow the green shoot, see the instructions below before cutting.

5Are sprouted onions toxic for pets?

Cats, dogs, and some other animals do not do well with onions—sprouted or not—and can get ill from them. If you have a pet that randomly nibbles, keep the onions and onion plants away.

6Can I regrow sprouted onions?

Yes. In fact, because they are already sprouting (growing), you’ve confirmed they can regrow and they have kindly given you a head start.

Some grocery store foods are treated with growth retardants to stop this from happening, but, if yours is sprouting, it’s good to grow.

The secret to most vegetable regrowing is the presence of the stem-growing tip, which for onions is the base where the little hairy roots grow.

You can grow/regrow your sprouted onion as a houseplant in a sunny location or plant it in your garden (either in containers or the ground). Often there are several plants sprouting within each onion. The instructions below will explain further.

7Are sprouted garlic bulbs safe to use?

Same story as the onions: they are safe for humans, but the taste is altered. If the sprouts have just started, cut them out and use the rest of the bulb for cooking.

If you want to try regrowing them, use the instructions below.

8How can I prevent onions and garlic from sprouting?

Light and warmth are the culprits.

Store both in a cool, dark, dry place with temperatures between 55 to 65°F (13 to 18°C). This is often a lower temperature than we have in our kitchens.

Moderate humidity will help prevent drying out.

It is not recommended to store onions in a fridge.

9Can I also regrow shallots?

Yes, if the bulb and roots are still intact. If you just have the green edible parts without the roots, no.

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How to Regrow Sprouted Onions

Have a look at the image above. It’s a cooking onion that has started sprouting.

To regrow it, you will be removing the sprouts right down to and including the roots, and setting the rest of the onion aside (you can use it for cooking if it’s still fresh).

Steps

1Prepare Pot

Get a pot with drainage holes ready. Fill with potting mix made for organic vegetable growing.

2Cut Onion Around Shoots

Using a clean knife (blades cleaned with isopropyl alcohol/ rubbing alcohol), carefully cut the onion in two (not down the middle or you will cut apart the part we want to keep whole).

3Reveal Shoots

Carefully cut onion open, revealing green shoot or shoots inside. Each one can form a new plant.

4Peel Outer Layers

Peel away the outer onion layers, leaving the entire shoot(s) with the base (roots) attached. They cannot grow without their roots.

I’ve outlined the part to regrow in yellow pen on the photo (above).

5Plant Onion

Plant each onion 2-inches or more apart, burying roots one inch in potting mix.

6Water

Water until damp, not soaking wet.

7Choose Sunny Location

Choose a sunny location and do not let the soil dry out.

8Harvest When Tops Dry Out

Onions are ready to harvest when the tops (greens) turn brown, floppy, and dry out.

This article on growing sprouted onions at Anktangle has good photos for each step.

So, there you go. Another one of life’s great mysteries demystified.

Let me know if you grow your onions and how it turns out. It can be quite different growing them indoors versus outdoors. I find indoors is always much slower, but I like having weird houseplants so it’s fine.

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~Melissa the Empress of Dirt ♛