Growing your own onions is one of the most rewarding things you can do in a veggie garden. While pros might use the word “breeding” to talk about creating brand-new varieties, we’re going to keep things simple and focus on how you can get a great harvest right in your backyard. Here’s everything you need to know to get started.
The Big Question: Sets or Seeds?
First off, you’ve got to decide how you want to start: with onion “sets” (those tiny baby bulbs) or from seeds. If you’re looking for the easy route, go with sets. They’re much tougher and usually ready to harvest in about four to six months. On the other hand, growing from seed is a fun challenge for seasoned gardeners. It takes a bit longer, but the payoff is that seed-grown onions often store better through the winter.
When and Where to Plant
Onions are sun-worshippers! Pick a spot in your garden that gets plenty of light and a good breeze. They aren’t too picky about the soil type, but they do love a bed that’s nice and loose and—most importantly—weed-free.
One pro tip: don’t add fresh compost or fertilizer right when you’re planting, as it can be too much for them. If you’re planning a spring planting, it’s better to prep the soil with nutrients the previous fall.
If you’re starting from seed, you can head out to the garden in late March, or get a head start indoors as early as February. For sets, you have two choices: “spring sets” go in the ground between March and April, while “overwintering sets” are planted in the fall (August to October) to get a jump on the next season.
The Harvest
Timing is everything! If you planted from seed, you’re looking at a harvest window between August and October. Fall-planted sets are usually ready by May, while spring sets follow closely behind in July.
Wait for a dry day to pull them up. You’ll know they’re ready when the green tops turn brown and start to flop over. A few weeks before you plan to harvest, stop watering them entirely to let them cure. If you end up with a massive haul, don’t worry—you can preserve your bounty by pickling them or roasting them for long-term storage.
Onion Growing Checklist
- Decide between easy-to-grow sets or rewarding seeds.
- Pick a sunny, breezy spot.
- Keep the soil loose and clear of weeds.
- Timing: Seeds in late March; sets in either spring or fall.
- Harvest: August–October for seeds; May or July for sets.
- Wait for the greens to dry and “lodge” (fall over) before harvesting.
- If your onions bolt and flower, you can actually collect the seeds to propagate your own next batch!
