Growing Onion

Allium cepa : Amaryllidaceae / the onion family

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

(Best months for growing Onion in USA - Zone 5a regions)

  • S = Plant undercover in seed trays
  • P = Sow seed
  • 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 8°C and 30°C. (Show °F/in)
  • Space plants: 5 - 10 cm 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

Your comments and tips

Post a comment or question Display Newest first | Oldest first, Show comments for USA | for all countries
09 Jun 22, Michael Pellerin (Canada - Zone 5a Temperate Warm Summer climate)
I Live in Miramichi, NB Canada and looking to what growing zone I am in and what type of oignions grow better, short day, intermediate or long day , or what varieties are better for my zone Thank-you
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23 Feb 23, Caroline (Canada - Zone 6a Temperate Warm Summer climate)
I believe we need long day onions here in Canada!
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17 Jun 22, Anonymous (Canada - Zone 4b Temperate Warm Summer climate)
Go to the blue tab above and work out which zone you are. Pick what variety you want to grow.
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02 Jun 22, Rick Nuffer (USA - Zone 7a climate)
do walla walla onions grow well in Utah?
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18 Apr 22, Graham Bower (Australia - temperate climate)
I have been growing butternut pumpkin and trombone zucchini in close proximity and saving seed for following season. I saved seed from each for this seasons planting. This year my produce appears to be a cross of thes two . Is this possible? Can these cross pollinate? The fruit has been huge and eats very much like a quality butternut.
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21 Apr 22, Anonymous (Australia - temperate climate)
I believe they do cross pollinate.
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26 Mar 22, Heidi (Australia - temperate climate)
I have some onion sets left over from last year and want to plant them. All the articles I have seen thus far talk about growing them from seed/seedlings. Ours is a temperate climate, so when is a good time to plant them?
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19 Apr 22, Graham (Australia - temperate climate)
Sets . Another word for seedlings. If they are still fresh and viable they should be OK. In saying that, I am surprised that they are still OK from last year. (Gardenate : 'sets' are usually small onion bulbs with brown, papery skin)
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29 Mar 22, Anonymous (Australia - sub-tropical climate)
Check the top of the onion page.
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21 Feb 22, Narelle (Australia - tropical climate)
Is Mackay too hot to grow onions? What's the best variety for up here? Thanks
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Showing 51 - 60 of 363 comments
See comments for all plants

Ferolyn: The black (sharp) bits in the "pom-pom" are seeds. Yes you will get onions off them if you plant them. No, once the Onion has flowered it is pretty useless as an onion. Evelyn: day length sets teh onions "growing' it's bulb. you need the onion plant to grow in height BEFORE it grows its bulb else you end up with "sort of" spring onions. In canberra with heavy frosts probably better to wait til mid winter before planting. Graeme: timing is the key. If you live near the bay then you should be good to plant mid-late april (depending on the variety) this will allow the plant to grow before it starts bulbing (longer days). I planted Hunter River Browns today (West Sydney) so I am expecting a harvest of HUGE onions Nov-Dec

- David

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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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