🌱 Spring onion

Spring onions are fast, compact and easy, and they add a fresh oniony bite to salads, stir-fries and sandwiches. Because they hardly take any space, they suit pots, window boxes and gaps between other crops as well as vegetable beds.

Sow them in short rows every few weeks from spring to late summer for a continuous supply, and sow hardy varieties in late summer to stand through the winter for very early spring pickings. They are also known as salad onions or scallions.

Varieties to try

White Lisbon (classic and reliable)White Lisbon Winter Hardy (for overwintering)Performer (strong and uniform)Red Beard (red and colourful)Ishikura (bunching type that does not form bulbs)

Sow thinly in shallow drills 1 cm deep, in rows 15 cm apart, from March to August. Seedlings appear in one to two weeks. For a regular supply, sow a short row every three weeks. Spring onions do well in containers and window boxes; use a pot at least 15 cm deep and sow thinly across the surface.

For an early crop the following spring, sow hardy winter varieties in late August to September and protect them with a cloche or fleece in hard weather. Thin gradually to 2.5 cm apart, using the thinnings in salads.

Top tips

• Sow a short row every three weeks.
• Sow winter-hardy varieties in late summer.
• Use a pot at least 15 cm deep.
• Keep seedlings weeded; they are slow to start.

Spring onions are low-maintenance. Water them during dry spells, as the shallow roots dry out fast, and keep the bed weeded because they are poor competitors. They do not need feeding in reasonably fertile soil.

Onion fly, thrips and downy mildew are occasional problems, but sowing in different beds each year and covering with fine mesh minimises the first two. Thin out overcrowded seedlings, as dense stands are more prone to disease.

Top tips

• Cover with fine mesh to prevent onion fly.
• Water in dry spells.
• Grow in a new bed each year.
• Do not let them dry out in pots.

Watch out for

Onion flyThripsDowny mildewOnion white rot

Pull spring onions when they are 15–20 cm tall and about as thick as a pencil, usually 8–12 weeks after sowing. They are best when young and tender; leave them too long and they become tough and strong. Loosen the soil with a fork before pulling to avoid breaking the stems.

Harvest some from each row at a time so you have a succession. Overwintered crops are ready from March to May. Any that you leave will keep growing and produce flower heads in their second year.

Top tips

• Pick when pencil-thick for the mildest flavour.
• Loosen the soil first to avoid snapped stems.
• Harvest from each row in turn.
• Overwintered plants are ready in spring.

Use spring onions raw in salads, sandwiches, salsas and slaws, or cook them briefly in stir-fries, omelettes and noodle dishes. Both the white base and the green leaves are edible. Char them on a barbecue or grill pan for a sweet, smoky side dish.

Trim the roots, wrap in damp kitchen paper and keep in the fridge for up to a week. You can also stand the roots in a glass of water on the windowsill and they will keep growing. Chopped spring onions freeze well in small bags and are handy for cooking.

Top tips

• Grill whole spring onions for a smoky side.
• Regrow the roots in a glass of water.
• Chop and freeze for cooked dishes.
• Use the green tops for garnish.