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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
    Red onion
  • Young brown 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

08 Jul 17, thulani (South Africa - Summer rainfall climate)
Hi, i would like to plant onions in mpumalanga and my area were I live its cold mostly when its rains its pours. So can my onions grow very well in such environment?
07 May 17, jimmy (South Africa - Dry summer sub-tropical climate)
may sell them while they're still green?
07 May 17, (Australia - sub-tropical climate)
Hello Jimmy, We need a bit more information. Do you want to sell the onions while they are small or when they are larger, before the tops die down. You can sell or eat onions at any stage but if the tops have not died down they will not keep very long.
22 Apr 17, Keikantseng (South Africa - Summer rainfall climate)
I an staying in Taunton village in North west province. Can I plant onion in April?
23 Apr 17, John (Australia - temperate climate)
Yes you can. Long Keeping varieties can be sown now.
18 Mar 17, irene (South Africa - Semi-arid climate)
every i plant onion they dont come out what can i do plss help or tips.
21 Mar 17, John (Australia - temperate climate)
Onions are generally fairly easy to germinate. They need to be planted about 3 times their diameter with soil. A good way to do this is to sprinkle the seed over a small area that has been broken up and is very fine then cover with some more fine soil. Keep the soil damp but not wet. When the seedlings emerge they will be very fine like a needle. keep them damp but not wet as they may get fungus problems. A spot that gets some sunshine and a bit of airflow is good. They will take about 4-6 weeks before they are ready to transplant into rows in the garden. They will take about 6 months to be ready to harvest and store (when the tops flop over and start to dry). I hope this helps. Don't hesitate to ask questions, we are here to help.
19 Nov 16, Atholl Selkirk (South Africa - Summer rainfall climate)
Where can I purchase onion sets in South Africa, Gauteng?
17 Oct 16, nompumelelo (South Africa - Semi-arid climate)
what is the best growing season for onions in KwaZulu Natal, South africa e.g feb-march? and ehat are the heat unit requirements
08 Jul 16, Andrew (South Africa - Summer rainfall climate)
is it possible for me to grow onion in summer and which variety of onion can strive better
Showing 1 - 10 of 30 comments

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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. 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.
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