Growing Onion

Allium cepa : Amaryllidaceae / the onion family

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

(Best months for growing Onion in Australia - sub-tropical regions)

  • S = Plant undercover in seed trays
  • T = Plant out (transplant) seedlings
  • 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 Australia | for all countries
21 Apr 16, Karina (Australia - sub-tropical climate)
Hi I've planted onion seeds directly into the garden bed and then mulched over the top. Should I have waited until the seedlings grew before mulching? I've heard that like carrots you are supposed to thin them out? What should I do? TIA
Reply or Post a new comment
30 Apr 16, Paul (Australia - arid climate)
Mulching over seed will not allow them to germinate and then push through to the sun. Onion, lettuce and carrot all grow well together (The Three Sisters) and need to "see the sun" to germinate well. I plant the three mixed together thrown over the bed and then water in stirring the top 5mm of soil in the process and then keep moist with a misting rosehead. They will then come up thicker than hairs on a cats back and effectively do not need mulch until you have thinned out the baby carrots to allow bigger ones to grow. Lettuce you can pick and let come again while the onions slowly get bigger. Trim dead and yellowing onion leaves to encourage more growth.
Reply or Post a new comment
11 Apr 16, theresa (Australia - temperate climate)
Which variety red, white, brown onions seedlings ,when to plant as I understand they are planted at different times to minimize bolting. Thanks
Reply or Post a new comment
06 Feb 16, barry rowcliffe (Australia - cool/mountain climate)
do mealybug in the ground effect onions,if so what remedy is there. thanks
Reply or Post a new comment
22 Jan 16, Heidi (Australia - temperate climate)
I have several onions that are sprouting. Can I plant them now? Our temperatures are very high in summer so they might not survive, but they won't keep until autumn.
Reply or Post a new comment
09 Oct 15, graham paul (Australia - temperate climate)
how do you grow pickling onions I have sown brown onions, regards graham
Reply or Post a new comment
02 Oct 15, Fred Spiegel (Australia - temperate climate)
What is the diference between a onion and a salad onion
Reply or Post a new comment
23 Apr 15, mark (Australia - sub-tropical climate)
what is the best type of onions to grow around coastial areas ie Brisbane Cleveland area
Reply or Post a new comment
28 Dec 14, Jan Bruinsma (Australia - sub-tropical climate)
I have 2 onions that have sprouted can I plant them? What can I plant at this time of the year? I am just starting and do not know much. Any help would be appreciated.
Reply or Post a new comment
14 Oct 14, Ralph (Australia - temperate climate)
I put a whole red onion into my "garden" about 2mths ago. Now have 5 long stems with what look like flower buds and grass like foliage. Do I separate the stems and replant? Any advice greatly appreciated.
Reply or Post a new comment
Showing 111 - 120 of 193 comments
See comments for all plants

Ask a question or post a comment or advice about Onion

Please provide your email address if you are hoping for a reply


All comments are reviewed before displaying on the site, so your posting will not appear immediately

Gardenate App

Put Gardenate in your pocket. Get our app for iPhone, iPad or Android to add your own plants and record your plantings and harvests

Planting Reminders

Join 60,000+ gardeners who already use Gardenate and subscribe to the free Gardenate planting reminders email newsletter.


Home | Vegetables and herbs to plant | Climate zones | About Gardenate | Contact us | Privacy Policy

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.
We cannot help if you are overrun by giant slugs.