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
27 Apr 16, Noel Oliver (Australia - temperate climate)
What month to plant red onion seed and brown onion seed
Reply or Post a new comment
30 Apr 16, Paul (Australia - arid climate)
Onions can be grown all year round and with regularly planting seed every month you will have a continuous crop. Always let the most vigourous go to seed so you have a constant supply as onion seed does not remain viable for too many years, 3 tops if you want good germination rates.
Reply or Post a new comment
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
19 Feb 16, Nico (South Africa - Semi-arid climate)
What variety will be ideal for South Africa, semi arid I believe you are not able to plant Australian Brown south of a certain latitude?
Reply or Post a new comment
17 Mar 16, Bee-Pie (South Africa - Summer rainfall climate)
Texas Grano
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
Showing 251 - 260 of 366 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.