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
  • Red onion
  • Young brown onion

Onions come in a range of colours and shapes and sizes. Brown - strong flavour and pungent. Usually good keepers for storage. White - milder but still flavoursome. Keep fairly well. Red - Mild, suitable to use raw in salads and sandwiches. The seedlings should be allowed to gain a bit of strength before planting out - usually 4 to 6 weeks will be enough. When they are big enough to handle, you can plant out. They start off looking like blades of grass.

They don't have to be in a greenhouse (though that would be ideal), any sheltered spot will do. The idea is to guard against rapid changes of temperature, especially at night.

Onions can be bought as young plants (sets or seedlings) from garden shops/nurseries to plant straight into garden beds. Choose your variety according to your climate and the time of year as some onions will grow better in the cooler months .

Onion bulbs should sit on the surface of the soil. Do not cover. They will take six to eight months to mature. Onions are ready when the tops start to dry and fall over. Pull them and leave to dry for a few days. Store in a cool, dry airy place. Use a net bag or make a string by weaving the tops together.

Culinary hints - cooking and eating Onion

Brown onions roasted whole with other vegetables are delicious.
Red onions add colour to salads or stir-fry.

Your comments and tips

Post a comment or question Display Newest first | Oldest first, Show comments for New Zealand | for all countries
09 Dec 23, Gill (New Zealand - temperate climate)
How much watering do onions like. On tank water so hoping not heavy drinkers
Reply or Post a new comment
14 Dec 23, (New Zealand - sub-tropical climate)
Just give a watering 2-3 times a week depending on how hot it is.
Reply or Post a new comment
20 Jun 23, Sue (New Zealand - temperate climate)
My onions got a rusty fungus on the last year how do I guard against this happening again. I grew the multiplying onions found them in the garden centre as Welsh Onions. They were great until they developed the fungus.
Reply or Post a new comment
24 Jun 23, jim (New Zealand - temperate climate)
Copper copper copper I had same problem last year onions,garlic and leeks sometimes gardening is a pain but I still do it ??? Remember to use a sticker "sprayfix" by yates is one but most garden chemical people do similar it helps to break down the surface tension so the spray does not just run off do it before it appears and repeat it several times during the season only problem with it raining constantly it's hard to do right now. P.S. my mum used to grow welsh onions in the UK when I was a boy never saw enything like rust ?
Reply or Post a new comment
10 Oct 21, jim (New Zealand - temperate climate)
I am interested in planting dates for onions all my seed packets put planting in late autum winter but they are differen on this site.My father always planted onion sets are they available in NZ
Reply or Post a new comment
13 Oct 21, Anon (New Zealand - temperate climate)
The guide here is only a guide subject to your local conditions. You could try planting now.
Reply or Post a new comment
11 Oct 21, Sassy (USA - Zone 9b climate)
Jim, you just missed the spring planting season, ending in September. You can sow seed starts, in doors, under grow lights, in February to transplant in April or direct sow in May. The spring planting season begins with sowing starts in Jun, transplanting in August, or direct sowing in September. You can find this information in the Vegetable and Herb tab, click on Onion, select your Climate Zone and look at the coded calendar. Good luck with your onions next Fall.
Reply or Post a new comment
02 May 21, Michele (New Zealand - cool/mountain climate)
I seem to have gotten white rot/fungus tha affects most onion varieties except spring onions- they will get it but very late on...does anyone know of a vigorous type of ordinary brown or red onion that might stave it off until I can harvest? Thanks.
Reply or Post a new comment
10 May 21, Tony (New Zealand - temperate climate)
try spraying regularly with copper, also good for rust.
Reply or Post a new comment
06 May 21, Anonymous (New Zealand - temperate climate)
Ring your local agricultural or agric company department about the fungus.
Reply or Post a new comment
Showing 1 - 10 of 35 comments
See comments for all plants

Since you are having problems with your Texas Grano -- I would recommend going to an Egyptian walking onion (or other walking onion). Video abojut the onion can be found here: https://www.bing.com/videos/riverview/relatedvideo?q=walking+onions&mid=17F7CAB6E4A914745E4A17F7CAB6E4A914745E4A&FORM=VIRE Additionally: the walking onion originated from a cross between the Welsh onion (Allium fistulosum), and the common onion (Allium cepa). The Egyptian walking onion, Allium x proliferum, is a member of the allium family and a great addition to the perennial vegetable garden. Egyptian onions go by many names, including tree onions, topset (or topsetting) onions, and walking onions. The seeds are slow growing, and can take several years for them to grow and flower. That’s why people grow them mostly from established bulbs. Every part of the Egyptian walking onion is edible, including the bulb in the ground, the stems, the flower, and the aerial bulbils. There are different varieties -- some zones 3-9 others 3-10. I would select a 3-10 for your area -- additionally some types grow substantial bulbs under ground -- others have small underground bulbs -- so select your variety based on your need. There are white, brown and purple walking onions. There is also the RED CATAWISSA WALKING onion -- which is not classified as an Egyptian walker -- but is still a walking onion: this variety for its larger sized bulbs and topsets that are much larger than the typical walking onion. All parts of the plant are edible. Walking onions are a standard choice for permaculture gardens and food forests -- they are very low maintenance - and very reliable -- so a good choice for anyone having difficulty growing regular onions.

- Celeste Archer

Please provide your email address if you are hoping for a reply


All comments are reviewed before displaying on the site, so your posting will not appear immediately

Gardenate App

Put GardenGrow in your pocket. Get our app for iPhone, iPad or Android to add your own plants and record your plantings and harvests

Planting Reminders

Join 60,000+ gardeners who already use GardenGrow and subscribe to the free GardenGrow planting reminders email newsletter.


Home | Vegetables and herbs to plant | Climate zones | About GardenGrow | Contact us | Privacy Policy

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.
We cannot help if you are overrun by giant slugs.