Salad onions

Salad or spring onions are easy to grow and take up little space, so can fit into even the smallest garden and do well in containers too. They are best sown little and often for regular pickings, and can be used whole in salads or finely cut in soups and stir-fries.

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  • Harvest

Month by month

Sow

Sow from March onwards for summer harvests, and in late summer and early autumn for a spring crop. 

Sowing small batches every couple of weeks will give continual harvests through summer and early autumn.

Choose a sunny site and prepare the ground by weeding and raking to remove lumps and stones. Make a shallow drill, 1cm (½in) deep, then water along the base. Sow the seeds thinly along the drill. Space rows 10cm (4in) apart.  

Seeds can also be sown in large containers filled with multi-purpose compost.

Grow

Thin the seedlings, if necessary, until they are about 2.5cm (1in) apart. The thinnings can be used in salads.

Water if the soil or weather is dry. Spread mulch, such as garden compost, around the plants to hold moisture in the soil and keep weeds at bay.

Common problems

Onion white rot
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.

Onion downy mildew
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.

Harvesting

Lift individual plants whenever required – they’re best when small and young, about 15cm (6in) tall, with the bulb no more than 1–2.5cm (½–1in) across.

You can harvest from spring through to autumn by making repeat sowings.

Recipes

Salad onions join forces with garlic and ginger in this Thai-style brassica stir-fry.

Recommended Varieties

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