A pinch of spring onion seed every three weeks, from March to July

Sow spring onions from early March to mid-July, a short row or a pinch in a pot every three weeks. Each sowing is ready in about 50 to 70 days, so you’ll be pulling them from late spring until autumn.

For an early crop next year, sow a winter-hardy variety from late August to mid-September. It sits through winter and is ready in March or April, when shop spring onions are at their dearest.

Sowing outdoors

1. Choose a sunny spot with fine, weed-free soil.
2. Make a shallow drill about 1 cm deep.
3. Sow the seed thinly, aiming for one every 2.5 cm or so. In rows, leave about 20 cm between them.
4. Cover, water gently, and keep the soil damp until they come up in two to three weeks.

Spring onions take very little room, so tuck them between slower crops: alongside carrots, between lettuces, or along the edge of a bed. Carrots, lettuce and beetroot all grow well next to them.

Sowing in modules

From February to March, you can sow indoors in modules, six to eight seeds per cell. Plant the whole clump out from late March to mid-April, about 20 cm apart. They grow as a little bunch, which is easy to pull together.

Varieties

• White Lisbon: the classic, quick and reliable for spring and summer sowings.
• White Lisbon Winter Hardy: for late summer sowings to stand through winter.
• Red spring onions, such as North Holland Blood Red: colourful and slightly milder.

Care

Weed carefully, as their thin leaves can’t compete with weeds. Water in dry weather, especially in summer. Dry soil makes them tough and pushes them to run to seed.

Winter sowings may need a cloche or fleece in the north or in very cold spells, though they’re hardy to around -10 °C.

Picking

Pull spring onions when they’re about pencil thick and 15 to 20 cm tall. Loosen the soil with a fork first if it’s dry. Pull the biggest ones and leave the rest to grow on. Each sowing gives about four weeks of picking before they get too big and strong.

If some are left behind, they swell into small bulbs. They’re still good to eat, a bit like mild salad onions.

Common problems

Onion fly. Yellowing, wilting plants with maggots in the base. Sow thinly so you don’t have to thin, which releases the smell that attracts them, and cover with fine mesh.

White rot. White fluffy growth on the base. It stays in the soil for years, so don’t grow onions, leeks or garlic in that spot again.

Downy mildew. Grey patches on the leaves in damp weather. Space rows wider so air moves through.

Spring onions are a perfect crop for succession sowing. Set your own frost dates on the spring onion page.