Regrow Green Onions And Sprouted Onions

If you’re like me and are avoiding supermarkets right now, you’ll be happy to know one trick that I use to stay at home. I’m sure you’ve heard that you can regrow green onions from just a tiny nub-end before. But did you know that you can also turn half-rotten sprouted onions into brand new full-sized onion plants?

I use green onions so often that I’m always running short. They don’t last in the refrigerator for long, their greens starting to wilt away within a matter of days. You can pop them into a glass of water in the fridge to prolong their lifespan a bit, but that only delays the inevitable.

Honestly, resprouting these is so easy that I’m surprised it’s not widely popular. It takes just a few minutes of your time, and in short order you’ll have more onions than you expect. Best of all, they’ll be healthy and vigorous, unlike those thin little things that you get when just soaking the root-end in water.

Ready to absorb a few tricks? If so, here we go!

Useful Stuff For Getting Your Onions Going:

Before we get started, we’ve got a great video that goes over full-sized onions. While we’ll be covering this here too, it’s worth a watch to see how you can regrow full-sized onions!

Green Onion Redemption

So you separated out bunching onions and planted them and grew them… or you bought them at the market. Either way, you’ve got harvested green onions ready to eat.

The first step is to use what you want of your green onions… and save the root end.

But before you cut, take a good look at your ends. Let’s look at a few different possibilities you might encounter:

Not The Best End
There’s not quite enough roots on this onion.

This onion end looks sort of bedraggled. It will likely grow, but it’s not in the best condition. The nodule to which the roots attach is still intact and not too discolored, so it’ll grow new ones from that over time.

Much better end
Very consistent root material, much better for growing.

This is nearly perfect. There’s an even selection of trimmed root material over the entire end, and those will all regrow. These are ones I’ll always try to save for replanting purposes. Ends like this can usually be regrown between 2-4 times with no problem as they’re vigorous with plump little tendrils to suck up water easily.

Might or might not do well
This one’s iffy. It’s discolored and only has a few straggly roots.

This one has seen better days. The rooting nodule has started to darken and discolor, but there are still a few protruding bits here and there. It might take root, but if it does, it’s probably only good for one more regrowth.

Every so often, you’ll find an onion that has absolutely no roots at all. It may even look like the entire end has been sliced off. Those will not regrow, so don’t waste your effort with those!

So now you’ve found some healthy, potential candidates. Cut off a 1.5″ to 2″ segment of white at the end. That’s what you’ll be regrowing from. You can go as short as 1 inch in length, but I find that a slightly longer one is better for regrowing.

Soaking in water
Soaking your onions in water allows them to develop new root matter and green tops.

Take those green onion ends and put them in cool water. Set them somewhere where they can get lots of light.

This is the stage at which onion regeneration starts. As it’s forming new roots and stretching out new green growth, your only daily task is to rinse off all the sprouting onions and change the water every day once or twice. The plant will handle the rest.

You do not want the water to become cloudy, as that’s usually not good for your young plants. Cloudy water is water that’s filling with bacteria, and you want these to stay as clean as possible.

Try to avoid covering the tops of these new starts with water. They need air as well as water to survive!

Over the course of the next 3-5 days, do your daily water-change and rinse, leaving them in a spot with lots of light. A sunny window or well-lit room should be fine, but the more light they get, the greener they will become. You’ll see new development gradually starting to form.

Three stages of new growth
Here’s three stages of new growth. The one on the left is just cut. The middle one is about 2 days after soaking. The one on the right is about 6 days after soaking and has very long greens.

At first, the cut end will slightly dome, then it seems to separate a bit. New green material will start protruding outward. The first leaf will still have your cut tip on it, but new leaves are very quick to follow behind. By the time one week has passed, you should have two stalks, one with a pointed tip and one with a flat one.

At the end of that week, it’s time to plant out all your starts into the garden or use the leaves fresh for cooking. If using, go ahead and remove the new growth just above your original cut.

To plant, you’ll need some good quality potting soil or an available garden bed. The soil needs to be well-draining but should hold onto some moisture, as your onions are accustomed to a lot of water now.

About to plant
Try to use a good quality potting soil if you can.

I blended two types of potting mix. One of them is a seed-starting mix, packed full of worm castings and other great material, but finer in particle size. The other one is a raised bed mix that has a lot of larger bits of wood or compost in it and some composted manure. The wood bits hold on to extra moisture, keeping the soil damp for longer during warm weather.

You don’t have to use a fancy blend if you don’t have something right at hand, though! Use what you have available to you. Even plain dirt from the back yard will work for this purpose. You’ll want to make sure it’s loose enough to work and to plant in. It’s better if it doesn’t dry out into a hard-baked surface in the heat, too.

Newly planted and ready to go
Spacing is not essential if you’re growing these for green tops.

If you space out your starts every 6″ or so, you’ll find they will grow to massive size. In fact, they might resemble leeks more than green onions. They’ll be a little tougher, but you can still eat them, and they’re good for cooking.

But if you want more fresh scallions, I plant 2″ apart or even closer. These will bunch together well and don’t need a whole lot of space. I planted out eight of them in this pot today, but in a few days I’ll be adding more in between those, and by the end of the week I’ll be able to harvest my first batch.

This is a form of succession-regrowing. If there’s enough water for all the onions in the pot, and rich enough soil, you can keep tucking new green onion starts into the same pot when you’re pulling out old ones. You can also just come by and harvest a few leaves.

Planted and watered in
Once your onions are planted, water them in well.

Don’t forget to water your green onions!

Regrowing Sprouted Onions

Have you ever gone to grab an onion out of the pantry only to discover it had green leaves growing out of its top? It happens to the best of us, but that onion is not ruined. In fact, you can regrow them from those onion sprouts.

Sprouted onion
This brown onion has a single sprout poking up from the top.

Today I have a brown onion. This one only has one sprout, but sometimes you’ll see two or three different sprouts poking out of there. I find that’s more common with red onion than with a brown or Spanish-style onion. Red ones just like to divide!

Your first step in reclaiming this sprout is to carefully start peeling off layers of the outer skin.

Peeling it down
Carefully peel it down layer by layer to avoid damaging the sprout.

As you’re peeling it down, you may encounter bits of mold. That’s just fine. Keep gently peeling it down, layer by layer. Save those outer onion layers for your compost bin, because they’re already past the point of eating. In fact, you may find soft spots, and it may have a pungent aroma. As long as it has a healthy green top, keep on going.

Found original stem
The original stem from the old onion is still partially in place.

With hard-stem onions like brown onions, you may eventually encounter the part where the original onion’s stem grew up from. You can just peel off that flat stem segment if you encounter it, it won’t harm your sprout.

Almost there
The sprout is almost peeled down farn eough, but the onion skin around the bottom is still wrinkled and loose.

As you get down in the layers, you may find that some of the inner layers are loose. You want to try to get down to a fairly plump inner sprout if you can without losing too many of the leaves.

Now, if you have multiple sprouts coming out of the top, be more careful as you’re peeling these down. You don’t want to damage any of those sprouts, because you’ll be able to separate them into individual onions later!

Down to the sprout
We’ve reached the firm sprout in the center!

Here, we’ve gotten down to the single sprout that was in this onion. If you look at the bottom, a whole lot of material has been taken off, but there’s a surprisingly thick layer of root-end there. The original end with the old dry root material is still at the base, then a layer of white where the onion had formed. Above that, there’s another brown spot.

Guess what? That’s the actual bottom of your onion sprout, which basically formed a new root segment on top of the old one but inside the onion. Since it was feeding off of the old onion, it didn’t have to actually put out roots, it was able to suck it straight from the old root segment.

But we don’t need the original onion’s root end, only the new one.

Remove excess onion end
Carefully remove the old onion end, keeping the new brown end for the sprout.

Being sure to cut between the old end and the dark brown spot where the new root end has formed above it, cleanly cut off the excess root material. Do not cut into that dark brown spot, you want that completely intact.

If you have multiple sprouts joined to a single base, and they all have brown ends, you can also slice off the original onion’s old roots. Then, carefully cut the base apart, making sure each sprout has some root end to work with.

Just enough rooting base left
There’s just enough rooting base left to grow roots from.

If you look at your cut end, you can see that it’s not like the rest of the onion. It’s almost like looking at a solid core. From that core, your new root mass will form.

Set that onion sprout into the cup with all of your green onion starts. If it’s viable, it will put out new roots from its cut end. Just like your green onions, you’ll want to rinse your onion sprout once a day and provide it with fresh water. Check the root end to see if new material is starting to grow. If so, wait until that lovely bundle of root tendrils reaches at least 1″ and preferably 1.5″ in length, then plant it. This may take up to a week, and sometimes a little more than that. These are a larger base, and as they make a bigger onion will need more root matter to survive.

When planting your sprout, I like to plant it deep. You want mostly green sticking up above the soil’s surface. Since most of that sprout was kept moist and it’s recently been peeled, it’s at risk of sunburn damage. Try to cover up most of the white part. If you like, mulch around it to cover any remaining white parts, but protection from the sun’s heat is important right now.

Make sure you keep the ground moist, and that your plant gets plenty of sunlight, and you’ll find a new onion to replace the one you lost. If you’re lucky, you’ll have three or four onions out of your original one and get more than you started with!

Regrow Green Onions
You can easily regrow green onions or older, sprouted bulb onions!

As you can see, this is pretty easy to do. I hope you try to stretch out that time between grocery store visits by doing this. Best of all, you’ll always have fresh and delicious scallions or home-grown onions at hand.


The Green Thumbs Behind This Article:

Lorin Nielsen
Lifetime Gardener

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