Grow Onions Indoors the Easy Way
All you need is some onion bulbs, proper soil and an empty five liter plastic bottle. The idea is to turn the empty bottle into a vertical growing tower that can support multiple rows of onions. Thoroughly wash, rinse and remove the label from the bottle. Take some scissors and cut a series of holes around the sides of the bottle that are at least an inch in diameter. Try to stagger the holes from row to row, placing each hole about an inch apart.
Some people suggest that you remove the top of the bottle just below the neck, whereas others say that the bottle will be stronger if it remains intact. If you cut off the neck, the bottle will expand as the onions grow. The concern is that it can burst and cause the soil and onions to fall out. However, keeping the bottle intact will limit the size of the onions, but they may end up maturing faster. Experiment with both options and see which one works best for you.
Add a layer of your favorite soil mixture until it just reaches the bottom of the first row of holes. Place the onion bulbs or sprouts atop the soil with their heads facing out through the holes. This will allow the onions to grow outward and increase the amount that you can produce in a single container. Loosely pack some more soil atop the onions and repeat the process for each row until you reach the top.
Don’t pack the soil too tight because water will need to percolate through the bottle. Don’t forget to puncture a couple of small holes through the bottom of the container as well. This will provide drainage and prevent the bottom rows of onions from rotting. Make sure that the green tops of all of the onions are poking through the holes and facing up and out.
Add some water until the soil is moist but not muddy. Onions like moisture, but too much water will cause the dirt to erode and the onions to collapse on top of one another. Place the container next to the sunniest window in the house. If the window is really cold, you can pull back the container a few inches to regulate temperatures better.
Keep in mind that if you purchase and plant onion seeds, they will take considerably longer to grow. It’s better to start with a couple of batches of bulbs because they only take a couple of months to mature. Seeds require about three or four. There are also many different varieties of onions to choose from that differ in taste as well as their ability to grow under various conditions. Green onions and scallions can be planted in a similar fashion, but they only take a few weeks to mature.
You will know when it’s time to harvest the onions because you can see them on the sides of the container. They will have a long, green sprout on top and the onion will be ready once they look like what you would find in a store.
It does take some time to get an onion supply rotation going, so plan a few months ahead of time to ensure that you have what you need. Using this project can produce up to 20 onions in one growth cycle, and adding more containers or choosing larger ones will increase what can be harvested. Try this out for yourself and see how a steady batch of home-grown onions can easily be included in your year-round gardening efforts.