Yes, you can plant a sprouted onion!
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 three new onions from one sprouted onion!
But, you can't just plant a whole 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.
I'll show you how.
So, grab your sprouted onion and let's go!
★ Steps to Plant a Sprouted Onion ★
Here's how to regrow a sprouted onion in just 7 steps from preparing your sprouted onion to harvesting and storing your newly grown onions. Easy enough for a beginner gardener to pull off.
Step 1: Peel the sprouted onion.
Peel off the "meat" of the onion, layer by layer, down to the center.
If your onion has sprouted, chances are some of the outer layers will be soft and may be starting to rot if your onion has started sprouting. If not, you can still eat the outer layers of onion that are not rotten, so don't toss them!
To get to the part of the onion you can plant, you need to peel away the layers of the onion bulb, all the way down until you get to just the clump of green sprouts.
I don't use a special tool for this. I just peel the layers off with clean hands.
Step 2: Separate the sprouts.
Once you get to the center of your onion, you'll want to carefully separate the green sprouts into individual plants.
Peel away any final layers of onion skin to reveal the separate plants if you haven't already.
Usually each sprouted onion will contain three separate plants! Sometimes less, sometimes more. It's a fun little surprise to see how many you will get.
Step 3: Separate each onion plant.
Carefully cut apart each spout, at the root, with a serrated kitchen knife.
Ensure that each sprout has some roots attached.
Step 4: Plant your onion sprouts.
Your onion sprouts will survive 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 to prevent them from rotting.
Where to Plant Your Onions
You will need to plant your onion sprouts in full sun.
Onions require a lot of light. 12 or more hours of direct sunlight is necessary. So find a sunny spot in your yard, with loose soil, and plant your seedling spouts.
How Deep to Bury Your Onion Plants
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.
Note: Planted onion sprouts will take about 3 weeks to look perky.
Step 5: Care for your onion plants.
Continue to water and weed around your onion plants. Fertilize as needed.
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. 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. Read more about how to test your soil for acidity.
Note: You do not want your onion plant to flower. If it does, the bolting process has started and the bulb will not continue to grow. You'll want to harvest a plant that has begun the bolting process whether it has a flower or not.
You can still use the onion bulb, it may just be small. Sometimes due to changes in temperature, an 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!
Step 6: Harvest your onions.
How Long to Let Onions Grow Before Harvesting
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.
If your onion does not flower then you can let it grow up until the first frost.*
How to Harvest your Onions
Harvest by pulling the onion out of the ground and then brushing them to remove dirt.
Do not wash your onions.
Do not rinse your onions to clean them off. You want to keep the onions dry to avoid rot. Allow them to dry then you can brush away any dirt.
Storing Harvested Onions
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.
Step 7: Cure your onions for storage.
This is important if you have a large harvest of onions that you won't use right away.
So, if you plan to store your onions for any length of time, 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."
How to Cure Harvested Onions
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.
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 After Curing
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!
★ FAQs ★
Onion plants rely on insects to be pollinated. However, when you're re-growing an onion from another onion that has sprouted, that plant has already been pollinated. So you can regrow it indoors.
Onions require a substantial amount of sunlight to thrive. They need 12+ hours of direct sunlight. Onions to not grow well in shade or even in indirect light. So if growing onions indoors, you will most likely need to use a grow light to provide enough quality light to meet their needs.
This depends where you live. Generally, spring is when you will want to plant. You will want to make sure that the temperature does not drop below 28°F (-2°C). You can keep your onion sprouts indoors for up to 6 weeks before transplanting to the ground if needed.
Note: The ideal soil temperature for onions is 50°F (10˚C) and above.
Yes, you can regrow any color onion that has sprouted! White, yellow, or red.
★ Recipes You'll Love ★
Once you've grown new onions, try making some yummy food with them!
I have a ton of easy recipes to give you ideas for what to make with your garden-fresh onions.
Browse all my super easy recipes and Pin your favorites for later.
★ More to Grow ★
Did you know you can also regrow a sprouted potato?
Jim Sanuk says
I was outside and my wife handed me 3 big sprouted yellow onions. So your article is super helpful. I will follow up with results and pictures.
Angela G. says
Awesome! Please do.
Amanda T says
Thank you for the detailed information! New gardener here, and finally have a house with garden space. I’m eager to get started! I plan on trying potatoes, onions, and even garlic this year (even though it’s late for garlic, I’m hopeful!). I’m in Idaho, so I’m not worried about the potatoes. 😂 Do you know of any other veggies we can grow from sprouts? I think this is the neatest thing ever!
Angela G. says
I have only experimented with onions and potatoes successfully. I tried celery last year and was able to grow a little plant, but didn't have luck regrowing a stalk. As I test others, if they work, I will post! Good luck with your garlic. I have not tried that myself, successfully but I think once you get it growing, it comes back year after year.
Caren says
You pull the garlic bulb out, just like onions You have to start fresh garlic bulb every year.
Kimberly says
I literally grow anything I buy that has seeds! We cut to soft of strawberries by merely cutting in half and sticking them in a medium pot with all purpose potting soil! We do potatoes and corn the same way! We did a peach by putting the pit in a zip lock bag and putting in the fridge for two weeks, this mimics winter, then remove it and break open the hull and take out the seed. Place the seed in a pot of soil and wait! We take kiwi seeds by rubbing half on a wet paper towel then fold it up, put in a zip lock bag in a warm sunny spot and in a week or so you'll get sprouts. Take the sprouts and put in a large pot!
Cut a bell pepper in half, fill with potting soil and put on a plate and water till they sprout, when you get sprouts take the dirt filled peppers and plant the pepper in a LG pot covering the bell pepper pot and water!!! There's really NO limit to what you can grow from stuff you eat everyday... Well not chocolate chip 🍪 🤣 they never grow for me lol
Angela G. says
Love this! I remember my mom always growing our avocado seeds. We never planted them outdoors because we didn't live in the right zone, but it was still fun to see a cute little tree grow from the seed! Too bad about the chocolate chips. lol
Monique Leslie says
This is great thanks so much. We got a bag of onions from the grocery store, which we rarely do. And they sprouted so quickly. I did not want them to go to waste.
LaQuita Desha Allison says
I’m so grateful to have come across your so very helpful yet simple teachings on ,How to plant a sprouted potatoes and onions.
My first time planting was not successful, very disappointing…. But I am at it again! I chose to do a little more research this time one plant at a time , to not be so overwhelmed. Coming across your article was the best thing yet!! I’m super thankful to you for helping by sharing your loaded knowledge and experience. I’m looking excitedly forward to finding more to learn that you’ve shares on my other choices of crop. May God continue to bless you and your family.
Donna Phillips says
I'm going to try for both wish me luck 🥔
Angela G. says
Good luck!!
James Kauzlarich says
Somewhere I saw an article about growing or regrowing just the top of a sliced onion that has sprouted. I left it open to read, but somehow lost the article.
Angela G. says
You would need some of the roots to regrow just the top sprout of an onion.
Emily Rhodes says
Thank you for this info, I've had a sprouted onion with the greens growing to a foot long on my counter lol! I just separated them, one both off the root, so I placed it in water to see if it would grow back like other plants can. It should do well as long as my dog doesn't eat it! Happy gardening to everyone 🤗
Angela G. says
Hi Emily, you want to plant the onion sprouts in dirt. Not water. Just water can rot the plant. Check out the post above for more details. Good luck!
Tina says
Gathering information for my 2023 garden and came across this page. I am fairly new at gardening, but it is becoming my obsession. This is my first try at onions. You have included absolutely wonderful information. It was very thorough and easy to follow. Very well written. Thanks so much for providing this for everyone!
Angela G. says
I'm happy to help! Good luck with your onions and garden this year! Feel free to come back and share some pic here if you'd like.
Liz says
Hi. I have put the sprouted onion in a jar with the bottom part barely touching water. It is starting to sprout rapidly and now the bottom of the onion was roots going deeper into the water. Can I still plant this onion into the ground the same way? By removing the layers and dividing into three parts? Or if this onion already "flowering"?
Angela G. says
Hi Liz, You should be able to still peel this down and separate the plants, then put them in some soil to grow. You will know if they flower. You will see an actual flower (it's not that pretty but it's a round white flower with lots of tiny petals) and it's usually after the plant gets fairly tall that it will flower.
VLP says
Hello can they be grown indoors if the process has started close to winter? Also will they die if they don't get full sun, for example a balcony?
Angela G. says
Yes they can be grown indoors with enough light. However, onions do need a substantial amount of light. 12 or more hours of direct sunlight is best. Depending on how much direct sun your balcony gets, you may need to supplement with a grow light in order for your plants to thrive.
Doret N says
Thank you! I am giving it a go!
Malachy says
This is so complete, all I needed was clearly stated.
Thanks a lot.
Sue says
I live in zone 8 and it’s now October. Can I still plant my sprouts or do I need to wait for spring or??
Angela G. says
H Sue, I would refer to the soil temperatures to be sure. The ideal temperature range for onion plants is 55º to 75º F.
Eric says
Thanks. That was very informative. How much watering does the onion need? Do I need to water it until I harvest?
Angela G. says
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 says
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. says
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 says
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. says
Best of luck with your Vidalia onion!