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?
Esther Colleen Weaver says
This isn't no comment but I want to tell thanks for the tip how to grow potatoes and onions..
Payton says
Hi! Thanks for all the info!! When you said, 'Your onion sprouts will hang around for up to 3 weeks' does that mean I can't plant them for three weeks?
Angela G. says
Hi Payton, you do not need to wait to plant. Three weeks is about how long they will stay plantable before they can start to dry up.
ID Spud says
I knew you could use the bottoms of little green onions. Good info about peeling down to the green onion part. I was going to just put the whole thing in the ground!
Angela G. says
Yes, it's one of those things you don't know that you don't know! Best of luck planting and gardening.
Becky says
Thank you for the info!!! I just started 7 starts in my house. Waiting for summer to plant in the green house. (Alaska). With food going up in price. We think before we toss away
Angela G. says
Good luck with planting in the green house! I agree, we have to save where we can.
Tish Webster says
@Becky, I’m doing the same thing..I’m actually trying to grow my own garden
Biga says
Very useful information especially the removing the skin
Dominique byrd says
I broke my sprout by trying to peel too much. 🤦🏾♀️ Going to try again next time
Angela G. says
Oh darn! You could still try to plant it if you want as long as there are roots you can probably grow something. It might not be perfectly round. Onions are pretty hardy.
Sheri says
I planted 19 sprouts from store bought onions that did their thing before I could cook with them. They are out in the garden bed as of today. Thank you for your very helpful guidance.
Angela G. says
Sounds like you will have a nice harvest in a few months. Exciting! Glad I could help!
Teresa says
Thank you, Angela. I will let you know how this works for me....
Angela G. says
Great! I'd love to hear how this works for you, Teresa!
consuelo barra says
Thank you for your information.
Can they be planted in a pit indoor?
Angela G. says
Hi Consuelo, Since onion plants require pollination, I believe they would need to be planted outside where there are insects such as bees to pollinate the plants.
linda says
@Angela G., Onions are pollinated by insects like bees, but pollination is only necessary for producing seeds, not for growing the edible bulbs.
Gloria Russell says
These sprouts resemble green onions. Are they? Can you eat them as you would a green onion?
Angela G. says
Hi Gloria, they are not the same as green onions but are similar and are edible. The flavor is a bit more mild than a green onion.
tricia lewandowski says
It's February and we just got a huge snowstorm , so when do I plant My green Sprouts
Angela G. says
You can try planting indoors in a very sunny spot in a large, well drained pot.
paula says
First onion experiment planted today
:-))
Angela G. says
Exciting! Good luck. 🙂
Stephanie says
@paula, how are yours doing? I just planted for the first time today. I’m so excited!
I just planted my first onion along with a sprouted garlic clove and 12 jalapeno seeds (egg carton starter) today! I also started composting! I'm excited 😁 says
@paula,
Jenna says
Thank you for this info! I just planted my sprouted onion. When I peeled mine, there was nothing to separate. There was only 1. So I guess it was just a single one maybe. We’ll see!
Angela G. says
Could be that it’s just one! Sometimes it looks like there is just one but there are actually two and you need to remove one more layer. You can usually tell if there are two though by looking at the top. You’ll still be able to plant it and if it’s two you’ll get two onions shaped like half circles. Good luck! Thanks for the feedback.
William says
Thanks for the help! My partner and I just *planted* the sprouting onions without peeling and splitting them!
Now, instead, we've got 4 onions growing!
Angela G. says
I did the same thing at first. Now you know! 🙂 Good luck. Enjoy your 4 new onions!
Antoinette says
Thanks for the great info. I have 2 huge red (spanish) onions that I had forgot in the garage. They had grown in the dark and cold with long green leaves (?), So I decided to look up how to save them. Thanks for bunches of great photos and information.
Angela G. says
Hi Antoinette, You're welcome! Good luck growing your red onion sprouts!