Growing Onion

Allium cepa : Amaryllidaceae / the onion family

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

(Best months for growing Onion in South Africa - Summer rainfall 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
  • 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

05 Nov 24, (South Africa - Summer rainfall climate)
Can I start sowing onion seeds in November. If so which type of onion is suitable
12 Jun 24, Portia (South Africa - Summer rainfall climate)
Can I plant onions in south Africa September month. I'm mpumalanga lowveld nelspruit.
29 Nov 23, Themba Peter (South Africa - Summer rainfall climate)
I have onions that need transplanting is it the right time, will appreciate the advice.
30 Nov 23, (South Africa - Summer rainfall climate)
You could try but it does say Feb - April.
08 Sep 23, enie (South Africa - Summer rainfall climate)
is there onion variety that you can grow around November in south africa
14 Sep 23, Anonymous (South Africa - Semi-arid climate)
Check the planting guide - Dec onwards.
22 Jul 23, Joseph (South Africa - Summer rainfall climate)
Is it okay to plant Texas grano onions in August and September. I am in mpumalanga, South Africa
19 Nov 22, Graham Hoorzuk (South Africa - Summer rainfall climate)
Advice on how to grow tomatoes and lettuce in Durban
04 Dec 22, (Australia - sub-tropical climate)
Google how to grow them and read the notes here.
27 Oct 22, Which onion variety do I need to plant in December (South Africa - Summer rainfall climate)
I would like to plant onion during the rain season, please advise me on which variety to plant.December - April
Showing 1 - 10 of 81 comments

I just have a balcony so I'm using pots to grow a few things, I was wondering how deep a pot needs to be for onions.

- Ciara

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 Gardenate 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 Gardenate and subscribe to the free Gardenate planting reminders email newsletter.


Home | Vegetables and herbs to plant | Climate zones | About Gardenate | 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. Gardenate 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.