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★ How to 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 sometimes get three new onions from one sprouted onion!
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.
★ Steps to Growing a Sprouted Onion ★
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.
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!
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.
Step 4
Now it's time to 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.
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.
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.
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.
FAQ: Can onions be planted indoors?
Onion plants are self-pollinators so they do not rely on insects to be pollinated. This means you can plant them indoors. However, 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 likely need to use a grow light to provide enough quality light to meet their needs.
FAQ: When should I plant my onion sprouts?
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.
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.
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!
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.
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!
★ Recipes You'll Love ★
Once you've grown new onions, try making some yummy food with them!
Browse all my easy recipes to get ideas for what to make with your garden fresh onions!
★ More to Grow ★
Did you know you can also regrow a sprouted potato?
Learn how to plant a potato that has sprouted!
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.
Awesome! Please do.
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!
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.
You pull the garlic bulb out, just like onions You have to start fresh garlic bulb every year.
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
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
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.
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.
I'm going to try for both wish me luck 🥔
Good luck!!
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.
You would need some of the roots to regrow just the top sprout of an onion.
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 🤗
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!
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!
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.
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"?
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.
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?
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.
Thank you! I am giving it a go!