Growing onions in a container

Credit: Flickr / SoraZG

Q: I want to grow onions in a container but I’m not sure how big it needs to be. I have limited space and I’m trying to make the most of what I have.

I am not sure if you mean regular bulb-type onions or green onions. Green onions could be grown in fairly small containers in lots of organic matter, with occasional liquid fertilizer (sea-related: kelp or fish.) Bulb onions are heavy feeders and slow growers, so growing them in a container may be a challenge. You would need a large container – you could try a #3 or #5 plastic pot – roughly 3 or 5 gallons filled with good soil with lots of added organic matter (compost, manure, etc.) Plant the onions according to directions in the West Coast Seeds catalogue – they’ll need room.

You could also use a rectangular-shaped box or container that was at least 20 cm (8 in.) deep. The easiest way to start onions is from tiny immature onions called “sets,” available now at garden centres and some grocery stores too. By the way, onions need full sun!