Growing Onion

Allium cepa : Amaryllidaceae / the onion family

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

(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

29 Nov 23, Themba Peter (South Africa - Summer rainfall climate)
I have onions that need transplanting is it the right time, will appreciate the advice.
08 Sep 23, enie (South Africa - Summer rainfall climate)
is there onion variety that you can grow around November in south africa
14 Sep 23, Anonymous (South Africa - Semi-arid climate)
Check the planting guide - Dec onwards.
20 Aug 23, Michael (Australia - temperate climate)
Can you please tell me the best varieties of onion to plant now. Live at Canowindra NSW Thanking you
06 Sep 23, Anonymous (Australia - sub-tropical climate)
Which ever variety you prefer.
22 Jul 23, Joseph (South Africa - Summer rainfall climate)
Is it okay to plant Texas grano onions in August and September. I am in mpumalanga, South Africa
20 Jun 23, Sue (New Zealand - temperate climate)
My onions got a rusty fungus on the last year how do I guard against this happening again. I grew the multiplying onions found them in the garden centre as Welsh Onions. They were great until they developed the fungus.
24 Jun 23, jim (New Zealand - temperate climate)
Copper copper copper I had same problem last year onions,garlic and leeks sometimes gardening is a pain but I still do it ??? Remember to use a sticker "sprayfix" by yates is one but most garden chemical people do similar it helps to break down the surface tension so the spray does not just run off do it before it appears and repeat it several times during the season only problem with it raining constantly it's hard to do right now. P.S. my mum used to grow welsh onions in the UK when I was a boy never saw enything like rust ?
15 Apr 23, Mike (Canada - Zone 3a Temperate Short Summer climate)
Growing onions from seeds What kind should I grow? When? Can I start then before winter, or do I start the seeds in January indoors?
26 Apr 23, Erin (Canada - Zone 5b Temperate Warm Summer climate)
You need a long day onion, you can start seed ahead of time indoors, do not save seed packets, they're only good for a year.
Showing 1 - 10 of 348 comments

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

- Adam Kulka

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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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