• Krista Green

The Best Tips for Growing Onions in Canada

Updated: 3 days ago


Onions are a vegetable used nearly daily in many of our kitchens. Onions are a cold hardy crop that grow well in the zone 3 gardening climate of Canada and other parts of the northern hemisphere. Onions belong to the allium family and can be beneficial in your garden as a companion to many plants as a pest deterrent. (See below.)


When planting long day onions in your garden in zone 3 Calgary, Alberta Canada plant onions in late April or early May.

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For many years I struggled to grow onions. Each spring I would plant onion sets around the end of May and by September most would be only slightly larger than my garlic. Thankfully some research, along with learning from mistakes I had made, pointed me to where I was going wrong and last year was my first ever, very successful onion harvest! Let me share with you a few tips for growing onions that I have found out over the past year.




3 Mistakes I Made When Planting Onions


  1. Not making sure I was growing intermediate day, or preferably, long day onions.

  2. Planting too late in the spring. (End of May vs. end of April).

  3. Planting the bulb too deep.


Let's take a look at the varieties of onions we should be growing in Canada.


Long Day vs. Short Day Onions


Onions are photothermic. That means they need enough hours of daylight to grow to their full potential.


One of the most exciting tips I have learned for growing onions is that there are long day, intermediate day and short day onions. Up here in Canada in the northern hemisphere (or in latitudes 37–47°), where the summer days are long and winter days short we should be planting long day or intermediate day (sometimes labeled day-neutral) onions. If you are northern Canada, go for the long day onions. Long day onions require 14 to 16 hours of daylight to mature. Near the equator intermediate day onions grow best and in the southern hemisphere, short day onions.


As long-day onion bulbs grow quickly when there are more hours of sunlight in the day, it is beneficial to plant onions as soon as the soil is workable and night temperatures are warmer than -6C (20F). With June 21st being the longest day with respect to hours of sunlight, planting onions earlier allows them to get the most out of the long days.


Long day onions varieties are great for growing in zone 3 Calgary, Alberta Canada in your backyard vegetable garden.