Keep your garden growing - see what to plant right now

Growing Onion

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

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

S = Plant undercover in seed trays T = Plant out (transplant) seedlings

  • 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

25 May 20, Mlungisi Zwane (South Africa - Summer rainfall climate)
when is the good time/season to plant onion in south africa?
25 May 20, Liz (New Zealand - temperate climate)
Have a look at this page www.gardenate.com/plant/Onion?zone=22
11 May 20, Caswell Tlali (South Africa - Summer rainfall climate)
What will happen to my onion if I plant it in August in Lesotho (particularly along Caledon)? I am in Berea district in Lesotho. My fields are on the bank of Caledon River.
22 May 20, Anonymous (South Africa - Summer rainfall climate)
Gardenate suggests you plant Feb to April. Try planting it in August and it probably won't even germinate. Most plants have a defined time of the year to grow in a particular climate zone.
12 May 20, Anon (South Africa - Semi-arid climate)
Check the top of the page .
10 Aug 19, Sam (South Africa - Summer rainfall climate)
I just planted onions that got spoiled and started to grow but now each bulb has grown into a set of seedlings. Do I pull them out and plant them separately or leave them grow as they are? Kind Regards Sam
13 Nov 19, anon (South Africa - Summer rainfall climate)
Pull apart.
01 Aug 19, Mwenya Selebi (South Africa - Humid sub-tropical climate)
Where in South Africa Gauteng can l buy red onion seedlings. l have a two hector onion field. l did direct planting of the onion and only one hector has come out well. l need seedlings that are ready for transplanting to supplement, csn you help me please. Where can l.buy seedlings in Gauteng.
18 Apr 19, SHIREEN WALTERS (South Africa - Summer rainfall climate)
Can I plant spring onions and coriander now (middle April) ?
29 Apr 20, Allimuthu Perumal 0329443959 (South Africa - Summer rainfall climate)
Yes you can but try a tomato box size for coriander
Showing 1 - 10 of 50 comments

Which varieties of onion can I plant in Johannesburg now. From seed

- Sally

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 our 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.