Easy to cultivate with a long storage life, backyard gardeners are growing onions (Allium cepa) successfully in most areas of Southern Africa. We rely heavily on these glorious globes for their sweet to pungent flavor and enjoy them fresh, dried or cooked in a number of dishes including salads, soups and souffle.
Onions are so popular, it’s easy to forget that the plump bulbs serve up a super-sized portion of vitamin C, they’re low in calories, and are high in minerals and dietary fiber. Other wellness benefits include cardiovascular health and cold and allergy prevention.
Choose a variety suited to day length in your areas (see above). Direct seed or plant sets, Plant into well-prepared soil in full sun, Keep well watered, fertilize regularly, Harvest by pulling bulbs and drying them for 2 weeks, Common pests and diseases are thrips, wireworms, botrytis rot and downy mildew
Onions grow best in full sun and deep, fertile, well-drained soil with plenty of organic matter. Work in a generous amount of organic compost or well-aged animal manure prior to planting. All varieties are shallow rooted and need constant moisture near the surface.
How to Plant
Starting from seed is often the only way to get classic, gourmet varieties. Sow indoors up to twelve weeks ahead of outdoor transplanting. Set out two weeks before last frost.
When planting onions allow 5-10CM between seedlings in traditional rows spaced 30-60cm apart. Mulch and weed thoroughly. Feed young plants with a high quality organic vegetable fertilizer and apply Liquid Fish & Seaweed later in the season to improve crop yields, taste and appearance.
Harvesting and Storage
Onions are ready to harvest when the tops fall over naturally, usually 80-100 days after direct seeding; 30-40 days from sets. Pull bulbs from the ground and let them air-cure for two weeks. Watering prior to harvest makes pulling easier. After curing, store the bulbs in a cool, dry place such as the cellar. Do NOT keep in a plastic bag.
Insect & Disease Problems
To prevent insect and disease problems rotate crops and avoid planting onions in the same area for three years. Thrips are suspected if the bluish-green leaves become bleached and wither. Damage to the lower portion of the stem is often caused by onion maggots. Wireworms (the larvae of click beetles) can also cause serious damage as they feed on all underground parts.
Common diseases include botrytis rot and downy mildew, both of which are characterized by soft tissue and mold.
Seed Saving Instructions
Every second year, select only the best bulbs and store 3-6 months at 4-7˚C. Plant out bulbs in early spring and allow them to form seed heads. When the heads start to dry, cut off the tops, dry further and thresh, saving the seed for next season.