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Growing Onion

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

04 Jul 17, Liz (New Zealand - sub-tropical climate)
When we say 'undercover', we mean somewhere which will not have extremes of temperature and cool down at night. e.g on a covered deck : or in a cool greenhouse.
12 Jun 17, Margaret Shaw (Australia - temperate climate)
I have planted about 100 spring onions about 2 wks. ago, all looking good, do they benefit from any fertiliser during the growing period. I dug in a small amount of compost before planting. Thanking you, Margaret.
15 Jun 17, John (Australia - temperate climate)
Onions like a good soil but do not like too much manure/fertiliser as it will cause soft growth which will be susceptible to fungal problems.
02 Jun 17, (Australia - temperate climate)
Hello, what does it mean when the onion doesn't form a proper onion bulb but the stem becomes thick. This happened to me last year after having a good crop the year before. Cheers
13 Sep 17, Karin (Australia - temperate climate)
I am having the same problem and I notice no-one has replied to the first person's question. The plant tops are thick and healthy, but there seems to be no onion bulb forming in the soil. Why is this and what can I do about it?
13 Sep 17, kelvan (Australia - temperate climate)
Old Italian method is to bend over the stalks to ground level
07 May 17, jimmy (South Africa - Dry summer sub-tropical climate)
may sell them while they're still green?
07 May 17, (Australia - sub-tropical climate)
Hello Jimmy, We need a bit more information. Do you want to sell the onions while they are small or when they are larger, before the tops die down. You can sell or eat onions at any stage but if the tops have not died down they will not keep very long.
04 May 17, Paul (Australia - temperate climate)
How deep do you plant the onion seedling if you buy a small tray from a garden centre or Bunnings?
06 May 17, Sean (Australia - sub-tropical climate)
Onion seedlings from punnets are usually very small.Make a V shaped trench abut 50 mm (2") deep and lay them along one side of the trench at recommended spacing (probably 100 mm (4") then carefully draw the soil from the other side of the trench over the base of the seedlings. This is best done on a cool overcast day or in the evening as a warm sunny day will stress the little seedlings too much. They might stay laying down for a few days but will soon be upright.
Showing 11 - 20 of 180 comments

Onions like a good soil but do not like too much manure/fertiliser as it will cause soft growth which will be susceptible to fungal problems.

- John

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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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