Growing Onion

Jan F M A M J J A S O N Dec
  S   T P P S   T      

(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 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

21 Dec 20, Anon (South Africa - Summer rainfall climate)
Go the onion page and check when to plant onions in your climate zone, or google and research about growing onions.
13 Oct 20, Kelly (South Africa - Summer rainfall climate)
Hi there, I planted white onions in May, they have not yet yellowed and the stalks have not fallen over- we're having a lot of rain fall early on and I am afraid they will rot if I leave them in the ground while it rains so much. Can I harvest them before they have yellowed or will they still mature correctly despite the rain? Any tips or advice would be much appreciated Thanks
16 Oct 20, (South Africa - Summer rainfall climate)
It says plant seed Feb Mar and you planted May, that is the problem. Check to see how big they are, if a good size pull out. You be the judge, keep an eye on them, if they look like going rotten out they come.
13 Oct 20, Liesl Mittan (South Africa - Summer rainfall climate)
We planted onions late in march , they are ready and some are flowering .They should dry in the ground , but we are having rain. What do I do . Take them out and dry them hanging or leave in the ground and hope for hot weather . Thanks
19 Oct 20, (South Africa - Summer rainfall climate)
Pull them out.
10 Sep 20, Vicky (South Africa - Summer rainfall climate)
I planted red onion seedlings in April. I was waiting for the tops to bend over, as I've read. But now they're flowering. When should I have harvested? Also. The necks are very thick.
11 Sep 20, (South Africa - Summer rainfall climate)
I don't grow onions but it says 24-34 weeks until harvest. It is probably time to harvest if they are going to seed. Pull out and allow to dry.
01 Sep 20, M.fourie (South Africa - Summer rainfall climate)
My onions grow big but don t have any bulbs.thy were planted from seedlings juni july and grow easy but till now no bulbs.we are in south of namibia
03 Sep 20, Anonymous (South Africa - Semi-arid climate)
Work out your climate type from the Blue climate Zone tab at the top of the page. Then check the planting guide. You may have planted out of season or at the very end of the season. Usually if something grows really well but doesn't produce a crop your soil is too rich, too much nitrogen.
17 Jul 20, Elaine (New Zealand - cool/mountain climate)
I am looking for everlasting onions. Think they are called Allium Cepa Perutile. They are what I would call a a shallot and grow from a shallot.bulb only and get lots around it a bit like garlic and have leaves like spring onions and don't flower or seed. If you Google Iitoi onions in USA they look like that. I moved from Australia years ago and they had grown in my family for generations. I would love to have them again. Does anyone know where I can get a few bulbs in NZ?
Showing 21 - 30 of 283 comments

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?

- Steve

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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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