Skip to Content

How to Plant a Sprouted Onion

How to Plant a Sprouted Onion

This post may contain affiliate links. As an affiliate, I earn a commission.

So, you have an onion or two that you bought from the grocery store, that have now sprouted in the pantry. And you’re wondering, “Can I plant these sprouted onions and regrow a new, fresh onion?”

In short the answer is, YES! You can plant a sprouted onion and grow a new one. Actually, usually you can get sometimes get three new onions from one sprouted onion!

Sprouted Onion
When your onions start to look rotten… Don’t throw them away! You can plant them and grow new, fresh onions that you can eat!

But, you can’t just plant the sprouted onion in the ground. You’ll need to do a little bit of prep work first. Don’t worry, it’s not hard at all.

Here’s how to regrow a sprouted onion…

Step 1

First, you need to peel the onion, layer by layer, down to the center.

Chances are some of the outer layers will be soft and maybe starting to rot if your onion has started sprouting. If not though, you can still use these outer layers of onion.

You want to peel all the way down until you get to just the clump of green sprouts.

Center of Peeled Sprouted Onion
Be careful to keep the original roots in tact. You’ll need those again!

I don’t use a special tool for this. I just peel the layers off with my hands.

Step 2

Once you get to the center of your onion, then you want to carefully peel away the additional layers until you start to revel separate plants!

Two plants inside sprouted onion

Usually each sprouted onion will contain three separate plants.

Step 3

Separate each onion plant by carefully cutting apart at the root with a serrated kitchen knife.

Onion Seedlings
You now have three onion sprouts!

Step 4

Now it’s time to plant your onion sprouts.

Your onion sprouts will hang around for up to 3 weeks before you need to plant them. You do not need to store them in water or soak them before planting. Do store them in a cool dry place though.

Onion plants don’t need to be buried very deep. You should plant the seedlings just 1″ into the ground and space them at least 4″ apart so the bulbs have room to grow.

Planted onion sprouts will take about 3 weeks to look perky. Keep them watered and plant them in a place that gets plenty of sun.

How Far Apart to Plant Onions - 4"

Step 5

Continue to water and weed around your onion plants.

Onion plants prefer to be watered in cycles rather than every day. So you can water them about once a week unless the soil and plants start to visibly look too dry. Avoid overwatering as this can rot your onion bulbs.

Fertilize if your soil is not very rich.

Onions grow best in fertilized, well-drained, somewhat acidic soil and they like full sun. You can use organic (manure, compost, etc.) or store-bought fertilizer to ensure your soil has the nutrients it needs to nourish your onion to its fullest potential.

Your onions should grow for about 3 months to reach optimum size which is when the bulb reaches the size of a baseball. You will be able to see the top of the onion as it grows and can get a good idea of its size without digging it up.

Onion Plants

You do not want your onion plant to flower. If it does, then you’ll want to harvest that plant.

Step 6

Harvest your onions.

If your onion does not flower then you can let it grow up until the first frost.*

Harvest by pulling the onion out of the ground and then brushing them to remove dirt.

Do not wash onions. You want to keep the onions dry to avoid rot.

If you’re ready to eat your onion, go ahead! They are ready to eat as soon as you pull them out of the ground. If you want to store them for later, read on.

*NOTE: If your onion plant flowers, unfortunately you will need to harvest whether it’s full size or not. The bulb will not continue to grow once the plant flowers since all the plants energy will be redirected to the flower. Sometimes due to changes in temperature, the onion plant will flower prematurely. This can happen just as a fluke too so it’s best to plant multiple onion sprouts for better odds of scoring a full-grown onion!

Harvesting onions

Step 7

Cure your onions for storage.

You do not need to cure onions. You can eat onions right out of the ground. However, if you plan to store them, then you’ll want to cure them first. Curing is easy. It’s essentially just drying out the onion and letting its skin become it’s protective “container.”

You can “cure” your onion for long-term storage by letting them sit in a warm place (75-80˚F) to dry up. You can hang them or place them in a wire basket or mesh bag with good airflow so all sides dry evenly. Trapped moisture may lead to rot so make sure all sides of the onion get exposure to air either by rotating the onion or hanging each onion individually. Some people lay them out in the garden and rotate them so all sides get a chance to dry out.

Curing onions

The green tops will dry up and the outside layer of skin will firm up. When the stems are completely dry, they are cured. Depending on the size and type of onion, it can take 2-6 weeks to completely cure the onion.


Once cured store your onions in a cool, dry place. Cured onions, depending on the type and size, can be stored for as long as 10 months!

And if your onion begins to sprout before you get to use it… you now know what to do! Use that sprouted onion to grow more onions!

Did you know you can also regrow a sprouted potato?

Learn how to plant a potato that has sprouted!

Now let’s make some yummy food!

While you’re here, check out my easy recipes to get ideas for what to make with your garden fresh onions!

Browse all my recipes

How to Plant a Sprouted Onion

Leave A Comment


Monday 19th of September 2022

Thanks. That was very informative. How much watering does the onion need? Do I need to water it until I harvest?

Angela G.

Monday 19th of September 2022

Hi Eric, You're welcome. You want to water them about once a week, not every day. Too much water can rot your onion bulb so give your plants water as they grow, only when the soil starts to look dry.

Dennis Okine Jackson

Saturday 6th of August 2022

Big ups! For letting us know for free how to grow onion from sprouted one. I never knew it is planted that way. You've opened my eyes though.Many thanks. But please is there onion seeds?

Angela G.

Tuesday 9th of August 2022

Hi Dennis, You're welcome! Yes, an onion plant does flower (it's called bolting) and the flower produces seeds. You can grow an onion plant from a seed, however, you will need two seasons to produce a full-sized onion bulb since onions are biennial plants. That means they grow from a seed, to a plant, to dormant bulb. The bulb remains dormant until the following season when the bulb can be re-planted and grown to full size the following year.

Mary C. West

Monday 11th of July 2022

Angela, We wanted to thank you for the detailed guideline, that was entertaining as well as very clear. We are trying this with a sprouted Vidalia onion and will enjoy the process thanks to you. Mary C. & Walker D. West Corralitos CA

Angela G.

Monday 11th of July 2022

Best of luck with your Vidalia onion!

Wendy Karen Campbell

Thursday 7th of July 2022

Thank you for the information. I have 1 question. You said they, the sprouted onions, may keep for 3 weeks before planting. Is that necessary or now that we have separated them, may we plant them now?

Angela G.

Thursday 7th of July 2022

Hi Wendy, you can plant them right away! No need to wait.


Friday 24th of June 2022

Thank you for your article. I'm so excited to see what happens, usually I work on my flower beds, first year for veggies!! Again thank you.

Angela G.

Saturday 25th of June 2022

You're welcome. Best of luck with your veggies!