Grow Onions ... for Free!




Introduction: Grow Onions ... for Free!

About: I'm a student product designer and tinkerer who loves to create. My focus is on designing things that can be both fun and accessible.

I'll let you in on a secret, you don't need to be a green thumb for this to work. And you don't even need to be an adult. This is a great way for big and little kids to learn to grow something edible.

Teacher note: onions take a long time to grow so it's a great idea to start this project at the start of the semester so your class can watch them grow!


Container e.g. glass, cup, empty yogurt container - let your mind run wild. And you can decorate it with feathers, stickers, googly eyes etc.

Onion scraps: brown onion, spring onion, green onions or red onion

Something to hold the onion - toothpick, kebab skewer. I find the metal skewers work best.

Tap water

Soil or potting mix

Step 1: Perfect for Even the Worst Gardener

Ok, I don't like throwing $$ away. So when I buy vegetables I like to work out what I can grow from the scraps. Turns out onions and spring onions are incredibly easy to grow. Tempt them with a bowl of water and they spring (no pun intended) into action. Eventually, you will plant them in soil but the main fun is watching the creepy tentacle-like roots grow and beautiful fresh green shoots appear on top.

Step 2: Stake Night

So, you have some onion scraps, now it's time to make them into more onions.

  • Pierce a hole through the onion base, for large onions I use 2 stakes.

Step 3: Fill It Up

  • Place the staked onion on the top of a container.
  • Artist? Now's your chance to let your inner artist shine, decorate your container as you please, or don't.
  • Fill the container with water to the base of the onion. If it has roots guide them down so they dangle into the top of the water.
  • Place in a sunny spot like a windowsill.

Step 4: Change the Water

You don't like drinking dirty water and neither do your onions.

  • Change the water daily.
  • As the roots grow longer you can add less water. Only the roots need water.
  • Over the next few days, you will see the roots grow longer and new onion sprouts appearing.

Step 5: Operation

This onion is about 2 weeks old. It's looking pretty healthy and soon it will be time to transplant it into soil. I recommend waiting a few more days so the smaller green shoots are more established, but I wanted to show you the steps so I pushed on.

To do this:

  • remove the stakes.
  • gently peel off the outer layers.
  • use a knife to separate out the different onions. The onion pictured had grown 4-5 new onions!

Step 6: Planting

  • put them in some potting mix or soil and give them a good watering.
  • onion plants should be spaced 4 to 6 inches apart in the row, with rows 1 to 2 feet apart.
  • water about once a week depending on your weather conditions.

Note: I need to buy more soil so at the moment they're in with other seedlings. But you should follow the advice above and give them space to grow.

Step 7: Harvesting

If your sprouts grow into flowers, wait until the flowers go to seed, then save the seeds for planting next season. These seeds will produce more onions!

If they grow into onions, bingo! Pat yourself on the back. Now, what to make?

You can also harvest the spring onion sprouts to use as a garnish in your cooking.

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3 years ago

Wow! I edited my reply to remove the offending word. Sorry.


3 years ago

I used to do my green onions in water for a week, but now I just plant them direct, no matter if they're store bought or from seed, they always regrow. I just water a little heavier the first few days. Thanks for the lesson. :)


3 years ago

I am sorry but what has grown is not onions but onion leaves, they can be eaten, no onion bulb will grow as the actual onion was picked and the final result will onion seeds no bulb, same with celery, carrots, and other similar root vegetables. Once picked the above mentioned vegetables will develop roots and leaves but not actual vegetables. I refer you to this


Reply 3 years ago

I've had no problem growing new onions or potatoes from scraps of old, unused onions/potatoes. It works just like the instructable says. And no, they are not just 'leaves' but whole, edible vegetables that are being produced. I'm not sure what you are doing that is causing a different result from me, my wife, my dad, grandfather, and everyone else in my family that gardens.


Reply 3 years ago

"Not sure what you are doing wrong."


That last word's not the best choice. Maybe 'differently' would be a kinder, gentler alternative?

There are, after all, a significant number of variables at play and another's experience would seem as valid as one own absent a detailed listing of the 'play by play.

I, for one have re-grown (what I call scallions) by saving the roty white bits and immersing them in water similar to what is shown here.

So far, no onion!

I did transplant a few of these to a container in the front yard and watched them grow into huge 'scallions' for the past four years or so. Surviving Winter temps (as low as) as nineteen degrees over four years now.

They did 'go to seed' I suspect - a little growth on the end of each scallion looking something like a dandy lion ;)

I know one can grow taters from old taters with eyes and have done so once or twice.

I have seen Onion scraps take root in the compost pile and do quite/surprisingly well 'till the chickens scratched their way about adding their contributions to the compost hoped for.

We build upon one another's experiences.

Think of Wilbur and Orville


Reply 3 years ago

If the objective is to produce something and a person doesn't reach that objective, something went wrong. Why is everyone so touchy with words nowadays?