Growing Onions From Seed

You can do this! Here’s my growing tips:

Sets vs. Seeds
Onions can be grown from seed or from sets. Sets are onions that have already started and formed small bulbs. I’ve had success with both.

Light Requirement
Onions prefer 6-8 hours of sun per day.

Location
Plan for a spot with access to plenty of moisture as onions are slow drinkers. They do well in damp soil but need drainage… soaking wet feet leads to rotting bulbs.

Onion Type
Know your zone and onion type. Long day onion varieties are generally best suited for zones 6 and lower and require 14-16 hours of daylight. Short day onions need about 10 hours per day and work for zones 7+. Day neutral onion varieties are pretty adaptable with about 12 hours of sunlight needed daily. Ideally suited for zones 5 and 6.

Choosing Storage Varieties
If you’re planning on storing onions over the winter, grow storage varieties suited for long term keeping. My favorites are Aisla Craig for short term storage and Stuttgarter, Yellow Sweet Spanish, Patterson, and Yellow of Parma for long term. I’m not really a red onion person so can’t speak to that as much. 😉

When to Start
Seeds are slow germinating and can be started in January with transplanting in spring into the garden.

Other Onion Options
Leeks, chives, Egyptian walking onions, ramps, and welsh onions are all great varieties to add to your must try growing list! Most of these are perennials too.

Maintain
Keep onions well weeded as they don’t like competitors.

Companions
Plan to grow onions alongside brassicas like broccoli, cauliflower, kale, and kohlrabi. They help to repel cabbage worms/moths with their strong scent when closely grown together. Greens, tomatoes and carrots are also good companions. So are fruit trees! Onions are great in guilds.

Never plant onions near peas or beans, peanuts or groundnut, nor asparagus. They stunt one another’s growth.

When to Harvest
Harvest onions when they tell you to; their greens will usually fall over and begin to yellow. You can also see their papery skin above ground level on the bulb.