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
  • 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

27 Mar 24, Peter (Australia - temperate climate)
Last year I had quite a few of my small Onions and Parsley cut off at the base. I suspect the culprit is a Blue Tongue Lizard, i have noticed full grown and baby Blue Tongues in the garden. While I dont want to hurt the Blue tongues, I want my crop to grow. I saw somewhere that Lizards dislike Vinegar. I am going to spray a row of Onions with Vinegar and see if this keeps the Beasties away. Has anyone tried this, or any similar way to deter Blue Tongues. Cheers. Pete.
25 Oct 24, Nadege (Australia - temperate climate)
I imagine the best way would be to cover the plants with some wire bird netting, it can be easily bent into shape and onions and parsley will be able to grow through it but I'm not sure the lizards will climb the wire. the other alternative could be to have a dedicated feeding spot where you could provide small amounts of green waste for the lizards so they don't come after your plants.
20 Aug 23, Michael (Australia - temperate climate)
Can you please tell me the best varieties of onion to plant now. Live at Canowindra NSW Thanking you
06 Sep 23, Anonymous (Australia - sub-tropical climate)
Which ever variety you prefer.
12 Apr 23, marco (Australia - sub-tropical climate)
hi i live on the gold coast Queensland . i have planted my onion 2 weeks ago in the cloudy times .ok .then we hit harsh sun times .i had to cover and they are ok growing well .if u just leave them in the sun they fry .....my second batch i lost maybe half my crop ...
27 Sep 22, Dalton Thomas (USA - Zone 2a climate)
Im from Tropical rain season all year round area and Im planing to grow white onion. How can I succeed on growing bunch of white onion. Any good idea? Im from republic of Palau.
29 Sep 22, (Australia - tropical climate)
Try planting at the begining of your driest part of the year.
23 Aug 22, Adam Kulka (Australia - temperate climate)
Could you please advice why always my onion growing seeds heads, I try to grow from seeds or from last year young ones but no luck to have nice bulb in end of the growing season, I'm in Suthern Highlands NSW, thank you
29 Aug 22, (Australia - sub-tropical climate)
Do you plant the right time and is your soil fertile. Plants will go to seed if nutrient runs out. Regular watering also.
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.
Showing 1 - 10 of 193 comments

Why are my brown onions growing up as spring onions?? I have even rung the company of the seeds and they sent me two new packets of seeds out. I planted some of them and they are still coming up as spring onions. Please help

- Sandra Millhouse

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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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