Red onions
Adding colour and a milder flavour to dishes, red onions are a versatile crop. They can be grown from seed, sets (small bulbs), or young plants, and stored for months over winter.
Red onions (Onion sets, 50)
£3.49 in the shop
Calendar
Sow
January – March (indoors for larger bulbs); March – April (outdoors for main crop)
Plant out
March – April (onion sets); May – June (transplanting seedlings)
Harvest
July – September
Conditions
Sun
Full sun, 6–8 hours a day
Water
Keep consistently moist during dry spells; reduce watering as bulbs mature to prevent rot
Soil
Fertile, well-draining, pH 6.0–7.0
Spacing
10–15cm (4–6 inches) between plants, 25–30cm (10–12 inches) between rows
Containers
Possible in large, wide containers at least 20cm (8 inches) deep, but yields may be smaller
Indoors
Start seeds indoors for a head start or for early crops; mature bulbs need outdoor growing
Care and harvest
Feeding
No heavy feeding required; a general-purpose fertiliser can be applied before planting
Pruning
Not required; remove any flower stalks (scapes) if they appear to redirect energy to the bulb
Harvesting
Harvest when foliage yellows and starts to flop over. Dry in the sun for 2-3 weeks before storing.
Storage
Store in a cool, dark, well-ventilated place (e.g., in nets or plaited) for several months
Good companions: Carrots, Lettuce, Chamomile