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Growing Onion

(Allium cepa)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
  S   T P S   T        

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

S = Plant undercover in seed trays. T = Plant out (transplant) seedlings. P = Plant direct in garden where they are to grow.


  • 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 in same bed): Lemon Balm, Borage, Carrots, Beets, Silverbeet, Lettuce, Amaranth
  • Avoid growing in same bed: 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

05 Apr 14, Dave (Australia - sub-tropical climate)
My onions are growing ok but they are all lying down instead of standing up. Is there something I should be doing to make them stand up?
22 Feb 14, Ali (Australia - temperate climate)
I am still drying out on onions I have taken it the top the the onion(where all the seeds are) but they are still green. What do I do? When do I plant them? Would they turn out okay!!?
10 Feb 14, kathleen harris (Australia - temperate climate)
Can you recommend a variety of onion that I can grow for pickling. The pickling onions in the shops are too big and not nearly crisp enough.
06 Nov 13, doug Dewar (Australia - arid climate)
i have planted onions and spring onions over the top of pea mulch and a lot of seeds have germinated, i have been pulling them out as they come up and finally they have all gone.Should i use sulphate of potash to balance out the high level of nitrogen in the soil as i do not want to lose them because they take so long to grow,hoping you can help me,thanks doug dewar.
14 Nov 13, Norma (Australia - temperate climate)
I planted my red onions, in a patch where my beans were, they took twice as long to grow than my brown onions planted nearby in virgin soil, brown onions are almost the size of a Pomello, red onions are still coming on. Onions and pulses, beans and Peas) definitely are enemies
23 Oct 13, Anne (Australia - temperate climate)
what to do? my onions have developed flower stalks, it is mid-spring
27 Oct 13, Ferran (Australia - sub-tropical climate)
Are the onions ready to harvest? Could you harvest them? preventative ways to stop them putting their energy in to flowering are: cutting off the flower stalks, shading them, keeping them moist. Good luck!
26 Jul 13, Kathi Thomas (Australia - temperate climate)
Hi, I planted out gladalan onions and they are near my snow peas that are flourishing. It says not to plant near peas so (at the risk of sounding silly) does this include snow peas. I am in the shoalhaven area, Nowra
05 Jul 13, ANTONIO (Australia - temperate climate)
what to fertilise onions , can i use npk super potash chicken manure
15 May 13, Dave Coats (Australia - arid climate)
Garden bed Chillies? I live in one of the harshest areas of South Aust. Temps vary from -5 to high 40's. As a child here I saw a couple of Europeans growing them well. Would love some help. Cheers Dave.
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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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