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 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

14 Feb 19, mike (New Zealand - temperate climate)
You have worked out your temperate - looking under onions - it is in the calendar months near the top of the page.
12 Nov 18, John (New Zealand - temperate climate)
My onions growing in Napier are sprouting seed heads. Some are large seeming perhaps fully grown or close but some aren�t. Should I nip the heads and leave them or pull them immediately?
13 Nov 18, Mike (New Zealand - temperate climate)
The onions that are big and going to seed need pulling out now. In fact any that are going to seed need pulling out now. Look up the internet for more info.
02 Mar 18, Leigh (New Zealand - temperate climate)
Hi, I’m having fun growing potatoes, Kumara and even sweetcorn that have sprouted in the bottom of my pantry. Wondering if the same should work with a brown onion that has sprouted greens out of the top?
22 Feb 18, Trevor Smith (New Zealand - temperate climate)
If I was to sow seeds in February and plant out in say May would frosts have any adverse effect on them?
22 May 19, Mark Taylor (New Zealand - temperate climate)
Onions are hardy plants and so frost tolerant, they will survive the winter. My understanding is If you plant them in Autumn you can harvest them in spring as spring onions but you won't get bulbs. They need to be planted in the spring for them to develop into onion bulbs. This is because bulb formation only starts after the summer equinox when the days start to shorten.
26 Feb 18, Mike (New Zealand - temperate climate)
If you sow now you would transplant in 6-8 weeks. I think onions can handle some frost. Check on the net about this.
04 Dec 17, andrew heaps (New Zealand - temperate climate)
hi,my onions have thick stalks just above the onions them selves.is that normal?and if not what is the remedy?
29 Oct 18, hamish (New Zealand - cool/mountain climate)
more than likely planted a little too deeply at start warm regards hamish
11 Apr 17, nik (New Zealand - temperate climate)
I planted 50 red onion seedling last year and they all split into 3 or 4 more like shallots, so after 6 months I gave up and pulled them out What went wrong ? there is no red shallot variety is there?
Showing 11 - 20 of 25 comments

more than likely planted a little too deeply at start warm regards hamish

- hamish

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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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