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How to Plant a Sprouted Onion

How to Plant a Sprouted Onion


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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.

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.

Storage

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

W jennings

Tuesday 17th of May 2022

Thank you for sharing this information. I found it very helpful and easy to follow your instructions. You did a wonderful job from beginning to the end of all the stages of the onion process. Thank you

Angela G.

Tuesday 17th of May 2022

Thanks! I’m so glad you found my tips helpful. Good luck planting your onions!

Amanda

Tuesday 3rd of May 2022

I've been watering my new onion growth for about 1.5 months or so. I can see the bulb growing which is exciting. However, both my plants have started to bolt. They are flowering but do not look large enough... what should I do? How do i prevent this for next time?

Angela G.

Tuesday 3rd of May 2022

Hi Amanda, this is most likely due to temperature fluctuation. Sometimes even during a normal growing season, changes in temperature can trick the onion into thinking it's ready to seed prematurely. The best thing to prevent this is try to plant when the temperature is more warm and consistent. You can cover the plants lightly with a blanket to hold in warmth at night during the cooler months. That may help. Sadly, you'll want to pull this and start again with a new plant. You can still eat the onion even if it's not fully developed. Here's some more information about onion bolting that might be helpful to you: https://www.gardeningknowhow.com/edible/vegetables/onion/onion-bolting.htm

Yaz

Monday 2nd of May 2022

Great post, thank you.

Monique!

Saturday 30th of April 2022

Thank you so much for this! Can't wait for the bulb babies to grow 😋❤

Angela G.

Sunday 1st of May 2022

You’re so welcome! Good luck with your onion babies! :)

Melissa Hyatt

Sunday 24th of April 2022

Thank you so much for the information instead of throwing away onion now I might get three out of them. Your directions are so easy to follow.

Angela G.

Monday 25th of April 2022

You’re welcome Melissa! Glad you found the info helpful. Good luck with your three onions!