Forget about buying expensive grow lights, heat mats, aquaponic systems, fertilizers, and the like just to have some fresh green onions over the winter, and try this easy method instead. Onion towers were all the rage a few years ago, so there’s a good chance you’ve seen at least photographs of them floating around the internet. However, most people don’t know how simple and straightforward it is to create one until they give it a try.
Making the Onion Tower
All you need are these three things:
- onion bulbs (any variety will work)
- soil (also known as potting mix)
- container (you can use a 5L PET throwaway water bottle)
To begin, remove the water bottle’s cap and drill holes in its sides. You can use a circle of wire which then you need to form and heat to create the holes. If you can use that, a knife or hole saw would also work.
The holes should be at least 4 cm (1.5 inches) in diameter. Try to use a container that is 20 centimeters (8 inches) in diameter, so you can stack 4 onions in each tier for a grand total of 12 onions. Keep in mind that larger onions produce more and can be harvested over a longer period of time; so, we recommend fewer but larger onion bulbs rather than more but smaller ones, depending on the size of your container and onion size.
If you don’t have a way for the excess water to drain, your onions will likely rot in the container and you’ll be out of luck.
Fill the bottle with dirt up to the bottom of the first set of holes, and then set an onion bulb in each opening. If you place the onion flat on the soil with the roots facing in and the leaves facing out, push it down a little, and then gently push it against the hole as you fill around with additional dirt, the onion bulb should block the hole as firmly as possible, preventing the soil from falling out.
Once your container is full, you should repeat the procedures above and set it on a saucer or pot tray and water it thoroughly.
Now Wait
Yes, you must wait and water the onion tower on occasion, but only if the top 2 – 3 cm (1 inch) of soil dries out. The time it takes for the onion tower to begin sprouting depends on the temperature of the room it is in; if it is kept at a comfortable 18 to 20 degrees Celsius (64 to 68 degrees Fahrenheit), the sprouting process should begin in approximately 14 days.
Dig into some green onions
Once the onions begin to sprout, you will be eating them for every meal. The best part is that the sprouts will keep growing for months even if you clip them back repeatedly.
