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How To Grow An Onion Tower On Your Windowsill

We’re always on the lookout for interesting and fun gardening projects here at Rural Sprout. And this time, we’ve got a doozy for you.

Not only is this project fun, but it’s quick to set up, keeps some single-use plastic out of the landfill, and is a real gem for gardeners with limited space.

I’m going to show you how to grow onions vertically in a bottle.

Empty Coca-Cola bottle filled with dirt, and holes cut into it to plant scallions.
I know, it’s pretty ridiculous looking. But it’s pretty brilliant too.

Growing onions in a bottle makes perfect sense when you think about it. We often grow herbs indoors so we can have fresh herbs to snip off what we need, exactly when we need it.

In fact, Cheryl has an entire post about the best herbs to grow indoors.

11 Herbs You Can Grow Indoors All Year Round

And as anyone who loves to cook will tell you, (hi, friend) the key to an excellent meal is the freshest ingredients possible. Herbs bring flavor to a dish, and fresh herbs bring color too.

Chopped scallions on a cutting board.
Something is about to get very tasty.

Onions are another common and flavorful ingredient in your favorite dishes. So, it makes sense to grow them inside so you can have fresh scallions and onions on hand too.

Related reading: 5 Easy Ways To Freeze Onions

It makes me crazy trying to find scallions in the supermarket that aren’t all dinged up or wilted. And even if you do find nice bright green ones, good luck getting them to stay that way once you get them home.

Scallions with wilted and dried out tops.
Well, they were nice and green.

Instead, wouldn’t it be nice when you’ve got a recipe that calls for green onions to be able to grab your kitchen shears and snip a few from your onion tower?

Yes. Yes, it would be nice.

Let’s make a little room on your windowsill, between the thyme and basil for a bottle of green onions. You can easily regrow green onion scraps using a small soda bottle and never have to buy green onions from the store again.

(Do you know about all the vegetables you can regrow from scraps? Check it out: 20 Vegetables You Can Regrow From Scraps)

But our onion magic doesn’t end there. You can also grow full-sized onions vertically using a one-gallon water bottle. And you can still enjoy the green onion tops while they grow. So perhaps you should make room for two onion bottles on your windowsill

Empty bottles, a bag of soil, onion bulbs, scallion bottoms and a funnel.
Gather everything you need.

Here’s what you’ll need:

  • Lightweight potting mix or growing medium
  • Sharp scissors
  • Funnel
  • Houseplant drip tray or saucer for each bottle

For regrowing scallion/green onion scraps:

  • A small, single-serve soda bottle (12 or 16 oz works well)
  • Green onion bottoms, the white part, with roots still attached

For regrowing full-sized onions:

  • A one-gallon water bottle
  • Onion bulbs

Let’s Make a Green Onion Bottle

If you haven’t already, remove the label, wash the soda bottle with warm soapy water, and rinse well.

Bottom of a soda bottle with holes poked into it.
I was able to do this easily with embroidery snips.

Poke three small drainage holes in the bottom of the soda bottle using either sharp pointy scissors or the tine of a fork that’s been heated over the stove. Be extremely careful with this step! You could easily slip and cut or burn yourself.

Hands holding an empty soda bottle with holes cut into it

Again, being careful not to cut yourself, cut three dime-sized holes, equally spaced around the bottom of the bottle. Moving up the bottle about an inch or two and starting so every row is off-center from the one below it, continue cutting three holes to create rows.

Use the funnel to fill the bottle with potting mix.

Soda bottle filled with soil, funnel in top.
Things got messy.

As this part can be messy (potting mix will spill out of the holes), consider doing this step in your sink or placing the soda bottle on a tray first.

Once the bottle is filled, poke the rooted ends of your green onion scraps into the soil in each hole. Push them in at a bit of an upward angle. You want to plant the onions deep enough so they won’t fall out; around a centimeter deep is fine.

Hands pushing scallion bottoms into soil-filled soda bottle.
Just planting my scallions in my soda bottle, like you do.

Place your onion bottle somewhere sunny and warm and set a drip tray or saucer under it.

Water in your newly planted onions and let the bottle drain. Throw out any water sitting in the saucer.

Let’s Make a Large Onion Tower

The process to make a larger growing container using a one-gallon water bottle is nearly the same as using a smaller soda bottle. However, we’ll be cutting the top of the bottle off for this project. Cut it just where it starts to taper inward.

Gallon water jug with top cut off.

Poke four small drainage holes in the bottom using scissors or something hot, as I described above. Again, be extremely careful with this step.

We’ll be cutting holes around the outside of the bottle again to create our rows.

Use your best judgment to decide how many holes to cut into each side. I’ve got relatively small onion bulbs, and I don’t plan on letting them grow too large, so I’m going to cut two holes per side.

Gallon water jug with holes cut in sides.

Moving up about three inches, cut another row of holes for your onions. Again, use your judgment to decide how much room between each row you want to leave for onion growth. Continue making rows until you’re about three inches from the top of the container.

Adding soil and onions to the water jug.

Add your potting mix to the bottom of the container until it comes up just below the first row of holes. Poke your onion bulbs into the holes from the inside. You’ll want to make sure the green top is facing outside the bottle and the roots inside the bottle.

Cover the onions with more soil until you reach the next row of holes.

Hand adding more soil to the water just container.

Continue planting your onions as described above and filling with more soil until about an inch from the top of the bottle.

Plant several onions upright in the soil at the top of the bottle. Now, cover the onions with a little bit of soil. You don’t need to bury them to get them to grow.

Overhead view of top of onion tower filled with soil and onion bulbs.

Water in your new onion tower, and then let it drain. Place the onion tower somewhere warm and sunny on a drip tray.

Finished view of vertical onion tower made from a gallon water jug.

Because we’re using clear bottles, it’s easy to tell when your plants need to be watered. Keep the soil slightly moist but not soaked; otherwise, your bulbs will rot. It’s better to let the soil dry out a bit between waterings and give the onions a thorough soaking.

Related Reading: Grow Onions – How To Grow Onions From Seed Or Sets

What To Do Next

Your green onions will start producing new tops within a week or so. Trim them and enjoy anytime your recipe calls for fresh scallions. You can even pluck the whole onion out to use it if you like. You can always poke another green onion bottom back in its place later on.

Onions beginning to grow out of plastic water bottle.

Your larger onion bulbs will take a bit longer to grow, but because you can see the bulbs growing, it’s easy to just pluck them out when you decide they are big enough. Although you can also eat the green onion tops from these, they won’t have the same spicy pungency of scallions. They’re still quite tasty, though.

If you want the onion bulbs to grow, be sure not to trim all of the green onion tops from each bulb. Use only half of the stalks.

Turn your bottle or tower every few days, so each side gets plenty of sunlight.

This step is especially important during the winter. Once the weather warms, you can even move your onions outside if you wish.

Don’t forget to add fertilizer once a month when watering your onions.

When your regular onions have growned to the size you wish, dump them out of the jug to harvest them, and start another batch.

Make a few onion bottles to give to friends and family. If you’re going to a party where the hostess loves to cook, a green onion bottle makes for an unusual and interesting hostess gift.

A green onion bottle and an onion tower

That was pretty easy, wasn’t it?

I bet, after this project, you’ll never look at soda bottles the same way again. And searching for the perfect bunch of green scallions at the supermarket will be a problem of the past.

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Tracey Besemer

Hey there, my name is Tracey. I’m the editor-in-chief here at Rural Sprout.

Many of our readers already know me from our popular Sunday newsletters. (You are signed up for our newsletters, right?) Each Sunday, I send a friendly missive from my neck of the woods in Pennsylvania. It’s a bit like sitting on the front porch with a friend, discussing our gardens over a cup of tea.

Originally from upstate NY, I’m now an honorary Pennsylvanian, having lived here for the past 18 years.

I grew up spending weekends on my dad’s off-the-grid homestead, where I spent much of my childhood roaming the woods and getting my hands dirty.

I learned how to do things most little kids haven’t done in over a century.

Whether it was pressing apples in the fall for homemade cider, trudging through the early spring snows of upstate NY to tap trees for maple syrup, or canning everything that grew in the garden in the summer - there were always new adventures with each season.

As an adult, I continue to draw on the skills I learned as a kid. I love my Wi-Fi and knowing pizza is only a phone call away. And I’m okay with never revisiting the adventure that is using an outhouse in the middle of January.

These days, I tend to be almost a homesteader.

I take an eclectic approach to homesteading, utilizing modern convenience where I want and choosing the rustic ways of my childhood as they suit me.

I’m a firm believer in self-sufficiency, no matter where you live, and the power and pride that comes from doing something for yourself.

I’ve always had a garden, even when the only space available was the roof of my apartment building. I’ve been knitting since age seven, and I spin and dye my own wool as well. If you can ferment it, it’s probably in my pantry or on my kitchen counter. And I can’t go more than a few days without a trip into the woods looking for mushrooms, edible plants, or the sound of the wind in the trees.

You can follow my personal (crazy) homesteading adventures on Almost a Homesteader and Instagram as @aahomesteader.

Peace, love, and dirt under your nails,