Gardening Tips: All About Onions

Editor’s Note: This column last appeared on 24 January 2018.


What to do this week:

It’s almost time to plant onions. Yes, already.

This is seed catalog season, as you may have noticed by the previous few columns, but I must admit it is not actually necessary to place your order quite this soon, unless you are ordering onion seed. You will want to get your onions started indoors very soon. Other things can wait, but hopefully you have your full seed catalog order all ready to go now so you can get those onion seeds in time. It is almost the end of January after all! February or March is the best time to start onions from seed. I like to start mine by mid-February if at all possible.

Iowa Seed Co. (Des Moines, Iowa); Henry G. Gilbert Nursery and Seed Trade Catalog Collection [No restrictions], via Wikimedia Commons

Iowa Seed Co. (Des Moines, Iowa); Henry G. Gilbert Nursery and Seed Trade Catalog Collection, no restrictions, via Wikimedia Commons.

I recommend that people start their onion from seed rather than from the sets you will be able to buy at the garden centers a little later. This is because onions are biennial. They bulb in the first year and set flower in the second. Sets are onions that have been artificially kept small for a year to discourage them from giving you nothing much but flower the year you plant them. Even if you are lucky and don’t get much bolting, you will find that these onions don’t store as well as first-year bulbs from seed.

Another consideration is that when you order onion seed you have a much bigger selection. If you buy sets, you can usually just find yellow and red, maybe some sweet onions, and that’s it. With seed you will have a choice of flavor and texture, and be able to mix and match onions for storing with others or early harvest, or whatever you like.

For storage, what you want is an onion that is going to stay hard and pungent all winter. My personal favorite onion is a hybrid called Copra. That will keep well. It is as hard as a rock until the following June. Patterson onions also meet my long-keeper criterion.

Another interesting thing about onions is that they are day-length adapted. They need the time during winter when the days are lengthening to get established. From February until June, they put on as much growth as you give them time for.  At the summer solstice, when the days reach maximum length for your latitude, their bulbing trigger is set in motion. You want them to have from February until June to have put on a lot of vegetative growth before that happens.

This day-length adaption of onions is also why you should be sure to buy seed developed for your region. Canadian sources will be more dependable on this point, but if you order from an international source, be sure to check for this data. Good catalogs will provide you this information.

If you grow onions adapted to a southern climate, they will start to bulb in April, because they will be experiencing the length-of-day to trigger that as early as April. If you grow onions adapted to a northern climate, they will wait too long for the trigger and just not bulb. So, you have to get seed that is adapted to our latitude. If you plant in February, your onions will put on as much growth as possible before the summer solstice, then stop growing up and start growing out into bulbs.

Sets aren’t bad. They are a great stopgap measure, but keen gardeners usually move to seed. Order now and hope you can get them going by mid-February. Even if you can’t manage until March, you will find the results much superior to those from sets.

Featured image by J.M. Perkins (Firm); Henry G. Gilbert Nursery and Seed Trade Catalog Collection, no restrictions, via Wikimedia Commons.




Market gardener, farmer, workshop leader, seed-saver, political candidate and mother, Michelle Smith has spent over 30 years coping with the challenges of our bioregion and in the process has built a store of practical and technical knowledge. The Inverness resident has served on the board of Seeds of Diversity Canada and represented Alternative Producers with the Federation of Agriculture but can do nothing about her hair. She is pictured with a head of Club Wheat, a seed that shares her approach to hairdressing.




Backyard food gardener Madeline Yakimchuk caught the food-security bug in the early ’90s through Cuba’s Urban Agriculture Department, taking her first permaculture course and planting her first garden. She can often be found discussing food security, nurturing a plant-based lifestyle or trying to give away vegetables. Professionally, she is GRYPHON media productions but sometimes uses la bruja in her volunteer work, most notably in managing the garden column, which begins life as a telephone interview.





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