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

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.
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?
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.
13 Feb 19, robert samuel walker (New Zealand - temperate climate)
when is the best time to put in red onion in christchurch
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.
05 Mar 19, Carole (New Zealand - cool/mountain climate)
When is the best time to plant red onion seeds and what sort of fertilizer should I use do u use lime?
06 Mar 19, mike (New Zealand - cool/mountain climate)
Best time to plant - read the top of the page. Fertiliser - one with not a high N content. Lime - read up about using lime.
08 Apr 20, Harpreet Kaur (New Zealand - cool/mountain climate)
If you sow seeds of red onion indoor in April and wait till it can be transplanted outside..say in June.. Can it stay in the ground in cold winters harmlessly..n mature in summers to come around Christmas? Or will it die in cold weather buried in soil ?
09 Apr 20, anonymous (New Zealand - cool/mountain climate)
Go to cool/mountain NZ look up onion and look at the monthly calendar at the top of the page - read what S P &T mean and then apply that to your question.
Showing 11 - 20 of 35 comments

If you sow seeds of red onion indoor in April and wait till it can be transplanted outside..say in June.. Can it stay in the ground in cold winters harmlessly..n mature in summers to come around Christmas? Or will it die in cold weather buried in soil ?

- Harpreet Kaur

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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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