Sow thinly 1cm (½in) deep from March to September in rows 10cm (4in) apart. Sowing every 2 weeks will give a continual summer harvest. For a spring supply sow in late summer and early autumn.
Thin the seedlings, if necessary, until they are about 2.5cm (1in) apart. Water if the soil or weather is dry; mulching will help maintain soil moisture and keep weed free.
Onion white rot: A soil-borne fungus that can cause yellowing and wilting of the foliage above ground, while rotting the roots and invading the bulb beneath the soil. A white fluffy fungus appears on the base of the bulb and later becomes covered in small, round black structures.
Remedy: There is no chemical cure for onion white rot when it is the soil. It is important to avoid introduction to previously clean sites. It is transported in contaminated soil, for example on tools or on muddy footwear. Take particular care in areas where cross contamination can occur easily, for example on allotments.
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Onion downy mildew: A fungal disease that damages foliage and bulbs, resulting in poor yields. It is a particular problem in damp conditions.
Remedy: Avoid problems by make sure there is plenty of light and air around plants by sowing or planting at correct spacings, and by regular weeding. Avoid overhead watering if possible. Infected leaves can be removed.
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Lift the plants when the plants are small and young, around 15cm (6in) tall and the bulb is no more than 1-2.5cm (½-1in) across.
Salad onions join forces with garlic and ginger in this Thai-style brassica stir-fry.
‘Ishikura’:Long, slender white stalks which don't form into bulbs, making it perfect for salads and stir-fries.