
How to Grow Onions: Starting with Bulbs aka Sets
There are four ways to grow onions: via bulbs (otherwise known as sets), via seed, via seedling, or from an onion that’s already been used but has roots and a bulb intact. The last method is most common with green onions, which regrow quite successfully.
Today we are talking about growing onions from bulbs, as that is what I am currently doing in the garden. It’s Fall, so bulbs are all the rage, and onion bulbs are easy to snag at the nursery. Being a zone 10 gardener, we can actually grow some form of onion year-round.
Onion bulbs are small tiny onions that look like “Honey, I Shrunk The Kids!” onion version. They’re very simple to plant and give you a leg up from starting onions via seed. This also allows for some cold-weather tolerance, great for more Northern hardiness zones.
I’m going to give you Cliff’s notes bullets, because that’s what we really need, right?

How to Grow Onions From Bulbs:
- Start with well-draining and balanced soil (with about 3″ compost if possible).
- Onions like full sun – 6 hours minimum
- Plant your bulbs 1″ deep and fertilize with a nitrogen-rich fertilizer.
- Leave your bulbs in their paper and plant roots down.
- Plant about 4″ apart with rows that are double that
- Water those top 3″ of soil and then daily for about 5 mins until established.
- Keep your onion patch free of weeds
That’s it! The onion bulbs are what you’d get if you started seeds, before they shoot up greens, so it gives you a leg up, but produces a strong plant. I love them.
Harvesting Onions
From the time of planting your onion bulbs, it should take about 3-4 months to get to maturity. Once you’ve grown your onions, the fully mature bulb will start to pop up out of the soil, and the greens may yellow and flop over. That’s when you know they’re ready for harvest. Additionally, if the onions start to soften, they need to be pulled up.
Curing Onions
Once your harvest your onions, keep them in a warm and well-ventilated place for a couple of days to cure. Then they are ready to store – for up to a year!
With onions being such a staple to cook with, they are a garden staple too! I encourage you to try them this year and see what you think. There are few things as satisfying as pulling up those pretty onions!