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
  • 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

07 Sep 08, Jaci (Australia - temperate climate)
I am only just beginning to grow onion this year. I have heard that onion seed doesn't have a long life. Can you begin the seed's life by chitting? When harvested, how long does it need to be hung and dried for before it can be eaten. Also, how long will it keep for (if hung in the dark and kept dry)?
08 Sep 08, Ciara (Australia - temperate climate)
I just have a balcony so I'm using pots to grow a few things, I was wondering how deep a pot needs to be for onions.
15 Sep 08, barney (Australia - tropical climate)
i grow onions in winton... they are yummy =] i put horse manure on them and it works goodies :)
03 Nov 08, Alex (Australia - temperate climate)
My onion looks like this: i36.tinypic.com/otnl3c.jpg It's about the size of a commercial onion - do I need to leave it to mature or ripen, or is it ready to pull out and eat? Thanks
03 Nov 08, Chris (Australia - sub-tropical climate)
Alex, you can pick onions at any size to use right away, so you could use yours now. To keep onions they should harvested after the tops have fallen down and dried out.
15 Dec 08, mark (Australia - temperate climate)
please help,can someone please tell me the correct procedure for drying/storing onions.thankyou and merry xmas to all.
18 Dec 08, Steve (Australia - temperate climate)
Some of my creamgold and red onions are shooting to seed. Some have large healthy bulbs. Should I harvest them now?? Others have virtually no bulb. Can I cut the seed head off and let them continue to develop?
04 Jan 09, Jay (Australia - cool/mountain climate)
I have just pinched out the seed heads on a few that have formed. We are using them fresh from the ground right now, and are waiting for them to die back before lifting. First time onion grower, but am wrapped with the ease of growing and the harvest. All 150+ seedlings have produced 2 - 4" bulbs. Used seed trays for seed, them planted out at 5" spacing. No loses, and NO THINNING (I hate that bit!!!m lol re: carrots) Cheers!
09 Jan 09, stewart (Australia - cool/mountain climate)
Discovered onions growing (planted by previous owner of property) so I dug some up (brilliant white). All sizes and some throwing new ones off the roots?Cut a larger one up to find only about 4 layers and then solid onion? What's the go? Is this about storing and then they develop the other layers? I've not grown them before so have no idea.
14 Mar 09, Ferolyn (Australia - temperate climate)
I found a forgotten red onion in my cupboard few months ago and it already has aboiut 3inches of shoot. I planted it. Now I have a tall stem of about almost 3feet with a pretty pompom flower on it. Would i still have onion out of it? It now has little pids on the pompom. I broke one of its pods out of curiosity and it has little black round bits inside... is that the seed? Would i get onions if i plant those seeds?
Showing 1 - 10 of 192 comments

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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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