Growing onions and spring onions

Growing onions - spring onionsGrowing onions - spring onionsGrowing onions - spring onions
Growing onions - spring onionsGrowing onions - spring onionsGrowing onions - spring onions

Growing onions and spring onions

Granny Mouse Country House & Spa, with its serene and picturesque location along the Lions River, is known for its beautiful garden setting and its fabulous food, offered in the Bistro and superb Eaves restaurant.

“We love that our beautiful setting inspires our guests to find their inner green thumb and start creating their own works of art in their gardens, whether it’s planting florals or creating a vegetable garden.

It fills our heart tank to know that our gardens are appreciated and the cause of inspiration,” says Sean Granger, General Manager of Granny Mouse.

Take onions, for example, a staple of innumerable delicious dishes.

Growing onions is straightforward, although they are one of the ‘longest’ crops, taking anything from 4-7 months from sowing to harvesting. This represents quite an investment in time, space and resources, but it means that you can grow varieties that are not always available in the supermarket.

You can grow them in seed trays, and plant out in 4-6 weeks. Sow the seed at a depth approximately three times the diameter of the seed- best planted at soil temperatures between 8°C and 30°C.

Onions can also be bought as young plants (sets or seedlings) from garden shops/nurseries to plant straight into garden beds. Onion bulbs should sit on the surface of the soil. Space plants 5 - 10 cm apart.

Do not cover.

By July onions are halfway, or more, through their growing season and it is from that point onwards that the crop really requires attention.

Onions are generally disease and pest resistant and, although the growing period is long, they just need regular watering, especially during the first few months of growth, and fertilising. Success, however, depends on one thing: planting the right onion for the right area.

Onions need a certain number of daylight hours and particular temperatures before they will begin to form bulbs. There are ‘short day’ cultivars, others that are classified as ‘intermediate’, and still others as ‘long day’. ‘Short day’ cultivars such as ‘Texas Grano’, ‘Hanna’, ‘San’, ‘Shahar’ and ‘Red Creole’ are best planted in the area from Musina in the north down as far as Bloemfontein. The best sowing time is from February to the end of March.

‘Intermediate’ cultivars, such as ‘Australian Brown Skin’, are best sown from Kimberly downwards, including the Western Cape. The best sowing time is from April to the end of May.

‘Red Creole’ (short day) and ‘Hanna’ (hybrid) can also be grown in the areas suitable for intermediate cultivars – from Kimberly downwards, and again from April to the end of May.

Fresh Seed Required

Onion seed tends to deteriorate as soon as a seed packet is opened, so it is necessary to buy fresh onion seed each year. If you have any seed left over from last year, rather use it for spring onions so that a lower germination rate is not so disappointing. Spring onions are simply the seedling stage of bulb onions.

Soil Requirements

Onions like soil that drains well. Heavy, or clay soils, should be avoided or made more friable with the addition of compost. Because onions are such a long crop, include an organic fertiliser (3:1:5) in the soil preparation. Once the bed has been tilled, rake it to remove any stones or clods of soil so that the texture is very fine. Don’t plant onions in a bed where other alliums have been grown in the past three years.


Water regularly and feed monthly during the warm autumn months, and keep beds weed-free so that the onions don’t have to compete for sunlight and nutrition.


From August, as the weather starts to warm up, feed with a potassium-rich fertiliser like 3:1:5, or a liquid fertiliser. If the leaves start turning yellow at the tips it is an indication of a potassium shortage and not the onset of maturity. Do not use nitrogen-rich fertilisers as this can produce thicker necks, which don’t dry out properly and create an entry point for pathogens that can result in rotting later.

Harvest Schedule

When the leaves start to turn yellow and fall over to one side it is an indication that the final phase of maturation has started, so taper off the watering. Once most of your onions have ‘fallen’ then dig them up and allow the leaves to dry out before storing the bulbs. If dug up before then the bulbs may not have formed sufficiently, and they may not store successfully. Harvest times vary from region to region:

• July to August in very warm, frost-free areas such as Musina, Lowveld, parts of KwaZulu-Natal, and Dendron.

• September to October in warmer areas of Gauteng, North West, Limpopo and KwaZulu- Natal Midlands.

• October to November in cooler areas of Gauteng, Free State and Northern Cape.

• November to December in Western Cape.

Harvesting And Storage

Great care needs to be taken when harvesting onions so that they have a long storage life. Onions are not as tough as they look and can be easily bruised or damaged when dug up. Leave the onions on top of the beds for about two days to dry out in the sun. In very hot areas place straw or leaves over them to afford some protection from sunburn. If it is raining put the onions under cover to dry out. Once they have dried, store them in a cool, dry place where there is plenty of air movement.

Compatible with, and can grow beside lemon balm, borage, carrots, beets, silverbeet, lettuce and amaranth. Avoid growing close to peas and beans.


These are bunching onions that don’t form big bulbs.

Growing tips: Sow them directly in situ, or in seed trays and then transplant all year round, except for the hottest mid-summer and the coldest mid-winter months. They like full sun, fertile soil and regular moisture. Harvest when young for the best flavour. If you leave a few to go to seed, they produce white flower heads that bees and butterflies love and will happily seed themselves. Look out for seeds of red varieties, such as Red Rum, to add interest to your salads.

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