Growing Onion

Allium cepa : Amaryllidaceae / the onion family

Jan F M A M J J A S O N Dec
      S                
          T            

(Best months for growing Onion in Canada - Zone 3a Temperate Short Summer regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • Easy to grow. Grow in seed trays, and plant out in 4-6 weeks. Sow seed at a depth approximately three times the diameter of the seed. Best planted at soil temperatures between 46°F and 86°F. (Show °C/cm)
  • Space plants: 2 - 4 inches apart
  • Harvest in 25-34 weeks. Allow onions to dry before storing.
  • Compatible with (can grow beside): Lemon Balm, Borage, Carrots, Beets, Silverbeet, Lettuce, Amaranth
  • Avoid growing close to: Peas, Beans
  • Red onion
  • Young brown onion

Onions come in a range of colours and shapes and sizes. Brown :- strong flavour and pungent. Usually good keepers for storage. White :- milder but still flavoursome. Keep fairly well. Red :- Mild, suitable to use raw in salads and sandwiches. The seedlings should be allowed to gain a bit of strength before planting out - usually 4 to 6 weeks will be enough. When they are big enough to handle, you can plant out. They start off looking like blades of grass.

They don't have to be in a greenhouse (though that would be ideal), any sheltered spot will do. The idea is to guard against rapid changes of temperature, especially at night.

Onions can be bought as young plants (sets or seedlings) from garden shops/nurseries to plant straight into garden beds. Choose your variety according to your climate and the time of year as some onions will grow better in the cooler months .

Onion bulbs should sit on the surface of the soil. Do not cover. They will take six to eight months to mature. Onions are ready when the tops start to dry and fall over. Pull them and leave to dry for a few days. Store in a cool, dry airy place. Use a net bag or make a string by weaving the tops together.

Culinary hints - cooking and eating Onion

Brown onions roasted whole with other vegetables are delicious.
Red onions add colour to salads or stir-fry.

Your comments and tips

27 Oct 22, Which onion variety do I need to plant in December (South Africa - Summer rainfall climate)
I would like to plant onion during the rain season, please advise me on which variety to plant.December - April
27 Sep 22, DAVE MILES (South Africa - Summer rainfall climate)
Australian Brown are starting to have seed stems, should I cut them off or allowed to seed
29 Sep 22, (South Africa - Summer rainfall climate)
A plant going to seed is finishing it's life and producing seed to continue the cycle of life - new plants. A plant then puts most of it's energy into producing the seeds. Time to harvest now or real soon.
27 Sep 22, Dalton Thomas (USA - Zone 2a climate)
Im from Tropical rain season all year round area and Im planing to grow white onion. How can I succeed on growing bunch of white onion. Any good idea? Im from republic of Palau.
29 Sep 22, (Australia - tropical climate)
Try planting at the begining of your driest part of the year.
24 Sep 22, digna carwell (USA - Zone 10a climate)
Hello I lived in 10A zone I would like to know when is the best time to grow , onions , garlic, carrots and mist vegetables? Thank you in advance for your response.
03 Oct 22, (USA - Zone 4b climate)
Check the planting guide for each crop.
07 Sep 22, Don Cropper (South Africa - Summer rainfall climate)
I am growing Australian Browns which I grew inside green house and planted out.They are making flower stems but the onions aren't ready to pull out yet.Can I leave the flowers to grow or must I cut them off.
13 Sep 22, (South Africa - Summer rainfall climate)
Sounds like your soil wasn't fertile enough to produce an onion bulb. The plant is going to seed already.
23 Aug 22, Adam Kulka (Australia - temperate climate)
Could you please advice why always my onion growing seeds heads, I try to grow from seeds or from last year young ones but no luck to have nice bulb in end of the growing season, I'm in Suthern Highlands NSW, thank you
Showing 1 - 10 of 327 comments

Do you plant the right time and is your soil fertile. Plants will go to seed if nutrient runs out. Regular watering also.

- Anonymous

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This planting guide is a general reference intended for home gardeners. We recommend that you take into account your local conditions in making planting decisions. Gardenate is not a farming or commercial advisory service. For specific advice, please contact your local plant suppliers, gardening groups, or agricultural department. The information on this site is presented in good faith, but we take no responsibility as to the accuracy of the information provided.
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