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?
Angela says
Okay, so I found your article AFTER I had already planted my full onion. I did not peel any layers and the sprouts continued to grow. However, yesterday I noticed a flower. So, would I be able to harvest and start over? Or should I just trash them?
Angela G. says
Flowering typically means a garden plant is past the point of producing a quality harvest since the plant's energy is now focused on the flower/seeds and not on developing the fruit/vegetable. But you could try pulling it out and separating the individual sprouts then re-planting each one and see what happens. Prune off the flowers if there are any left before you re-plant. Good luck!
Andrew Kairis says
I left two plants together.... Is OK?
Angela G. says
I would pull them and separate the two plants. If the seed plants are stuck together, neither of them will have the correct amount of room to expand outward and grow into the ball shape of a typical onion.
KathyG says
I live in central MS and it’s already middle of May. Is too late to plant my sprouted onion?
Angela G. says
Nope! You should be good to go ahead and drop them in the ground and give them until fall to grow.
Maryanne says
Wow, so interesting. Will surely try this. I have 2 sprouted onions that I will experiment with. Thank you so much.
Angela G. says
You're welcome, Maryanne! Good luck with your onions!
Jimmy Bob Moon says
It's fantastic what we can learn when we read.
Kim says
Thankyou for this info. I waste way too many onions so im excited to watch them grow 🙂
Angela G. says
Good luck with your onions!
Angela G. says
I think you're safe to go ahead and pull it out of the ground as long as the spouted part is still green. Good luck!
Sharnika Thomas says
I planted the whole onion before I saw your story can I dig up and start over
Angela G. says
You're so welcome Silvia! Good luck!
Silvia says
Super! Very helpful! I'll plant my onions tomorrow!
Thanks so much!
CJJ says
HELLO THERE HOW MANY ONIONS CAN I PLANT IN A 8 INCH DEEP AND 12 INCH WIDE - I DID EXACTLY AS YOU SHOWED AND ITS READY TO PLANT IN A POT - I LIVE IN A CONDO AND IN CANADA CAN I LIVE MY POT OUT SIDE ?
THANK YOU SO MUCH
Angela G. says
You'll want to plant them 1" deep and space them at least 4" apart so they have room to grow to full size. Onion plants are hearty and can stay outside as long as the temperature is above 20˚F. Good luck!
Marylin says
@Angela G., Hi Angela, can I know what type of soil is needed? I am about to plant a sprouted yellow onion I found in my fridge . 😅
Angela G. says
Hi Marylin, Onions grow best in fertilized, well-drained soil. You can use organic (manure, compost, etc.) or store-bought fertilizer. Good luck!
Erica says
We are going to plant today but in PA (Early spring). Is it too cold to put out on patio? Or keep Inside till it's warmer?
Angela G. says
Hi Erica, Onions are supposed to be pretty hardly and do OK in colder temps. This gardening site says as long as it doesn't drop below 20˚you should be good and that late March or April would be a good time to start! Onions do take awhile to grow big so better to get them in early and just keep an eye on the crazy PA weather. 🙂 Good luck!
Ricky Allemond says
This is so cool and will definitely give it a try
Angela G. says
Nature is awesome! Good luck, Ricky!
Donna Petty says
Thank you for the tips. I am ready to give this a try...
Angela G. says
You're welcome! Happy gardening!
A Flinn says
Thanks. I'll give this a try.
Angela G. says
Happy to help! Good luck with your garden. 🙂