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     T      
        P P            

(Best months for growing Onion in New Zealand - cool/mountain 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 46°F and 86°F. (Show °C/cm)
  • Space plants: 2 - 4 inches 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

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20 Oct 17, Danie (South Africa - Summer rainfall climate)
I would plant onions (seedlings) in March and harvest in October/November or plant seed in trays during February.
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19 Sep 17, mayoche (South Africa - Summer rainfall climate)
can I grow onion in rain seasons
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08 Jul 17, thulani (South Africa - Summer rainfall climate)
Hi, i would like to plant onions in mpumalanga and my area were I live its cold mostly when its rains its pours. So can my onions grow very well in such environment?
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03 Jul 17, Paris (Australia - cool/mountain climate)
I'm about to start growing onions from seeds and it says keep them under cover until early spring when they are ready to be planted out, I'm just wondering exactly what undercover means. Does it mean inside undercover or just out of direct sunlight outside. "Undercover" is very vague and I don't want to mess these up.
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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.
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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.
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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.
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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
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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?
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13 Sep 17, kelvan (Australia - temperate climate)
Old Italian method is to bend over the stalks to ground level
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Showing 201 - 210 of 377 comments
See comments for all plants

Onions are generally fairly easy to germinate. They need to be planted about 3 times their diameter with soil. A good way to do this is to sprinkle the seed over a small area that has been broken up and is very fine then cover with some more fine soil. Keep the soil damp but not wet. When the seedlings emerge they will be very fine like a needle. keep them damp but not wet as they may get fungus problems. A spot that gets some sunshine and a bit of airflow is good. They will take about 4-6 weeks before they are ready to transplant into rows in the garden. They will take about 6 months to be ready to harvest and store (when the tops flop over and start to dry). I hope this helps. Don't hesitate to ask questions, we are here to help.

- 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. GardenGrow 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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