Green Onion Tower





Introduction: Green Onion Tower

Here’s a super simple way of having fresh green onions all winter long without the need to invest in grow lights, heat mats, aquaponic systems, fertilizers or whatnot. There are chances that you already saw at least pictures of onion towers circulating on the internet, it was a real fad a few years back, but people usually don’t realize how easy and straightforward it is to make one, until they actually try.

Step 1: Making the Onion Tower

You only need three things:

  • onion bulbs (any variety will work)
  • dirt (or potting soil/mix)
  • container (I used a 5L PET disposable water bottle)

Start by cutting off the top of the water bottle, then make holes all around. The holes should have the diameter of at least 4 cm (1.5 inches), I fashioned a wire circle and heated it to make the holes, but a knife or hole saw would also work. The container I used had a height of 20 cm (8 inches) and a circumference of 50 cm (20 inches), so I decided to go with 3 layers of onions and 4 onions per layer: 12 onions in total. Depending on your container and onion size you could make more or less holes, just keep in mind that bigger onions produce more and can be harvested over a longer period of time, I recommend fewer but bigger, versus more but smaller, onion bulbs.

You should also make drainage holes on the bottom of the container for the excess water, or your onions might just rot and not produce.

Once you got the holes made, start filling the bottle with dirt, fill until you reach the bottom of the first set of holes then place an onion bulb in each one. Just lay the onion flat on the soil, roots pointing inwards and leaves out, push it down a bit then gently push it against the hole as you fill around with more dirt, the onion bulb should block the hole as tight as possible so the soil doesn’t fall out.

Repeat the steps above until your container is full, place it on a pot tray or saucer then water thoroughly.

Step 2: Now Wait

Yes, you need to wait and occasionally water the onion tower, but only if the top 2 – 3 cm (1 inch) of the soil dries out. How long you will have to wait mostly depends on temperature, if you keep the onion tower inside, at an average room temperature of 18 – 20 C° (64 -68 F°) it takes about 14 days until it starts to sprout, if it’s colder it takes longer.

Here’s a quick story: in the previous years I bought the onion bulbs I planted from the local farmers’ market, but this year I got lazy and bought them from a supermarket; in the previous years, as I said, it took about 14 days for the onions to sprout, but this year it took them almost 40 days under the same conditions. It might be coincidence or it might be an anti-sprouting agent, who knows, too bad I don’t believe in coincidences.

Step 3: Feast Yourself on Green Onions

Once the onions start sprouting there’s no stopping them, you will eat green onions for breakfast, lunch and dinner. And the best part is that no mater how often you cut the sprouts back they’ll just keep on regrowing for months.

Thanks for reading and bon appétit!

You may copy this instructable as long as you link back to my blog ( or original article (

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    I just found out last week that my son really loves green onions. I will hit the recycling bin when I get home. I bet we already have a bottle I can use. There may already be an onion or two in the pantry ready to get thrown out cause it started sprouting. I did not know that is where green onions came from. I thought is was a separate species. My am I uninformed. Thanks.

    2 replies

    Commercial green onions are usually grown from seed, they're just young onions, as they age they grow a bulb and the green part dies off by the end of the season, these are the onion bulbs you buy at the store. But the onions are in fact biannual plants, meaning that in order to reach maturity, the bulbs will sprout the next year and eventually go to seed. So by planting onion bulbs we emulate this second year, the warmth and moisture makes the onion "think" it's spring and starts sprouting.

    Thanks for the info. I don't know how it could take me all these years to learn something so simple. If the onion is already growing, I will not even need to wait that long!

    Does it need to be near a window for light? If so, how many hours/day?

    1 reply

    I had onion bulbs sprouting in the cellar with practically no light at all, but the leaves were yellow/whiteish, if you want proper green green onions, then the more light the better. Furthermore: you don't even need to plant them in dirt or potting soil, any medium that holds moisture would do, be it sawdust, mineral wool, peat moss, etc., you don't need nutrients in the growing medium since they'll just consume the bulb in order to grow leaves.

    What's the purpose of planting grown onion bulbs again? You should use onion seeds.

    1 reply

    The purpose is green onions, you can't grow from seed in the winter without artificial lights. Plus this is way faster than growing from seed, a shortcut to green onions.