How to grow spring onions

Spring onions are a quick, easy and delicious crop
Image: Spring Onion 'White Lisbon' from Thompson & Morgan

Easy-to-grow vegetables that are ready to harvest in just eight weeks make spring onions a firm favourite. Perfect for use as a "filler crop" between rows of slower growing vegetables, this tasty salad and stir-fry staple can be eaten raw or cooked. Here’s how to grow spring onions from seed.

Which spring onion variety to choose

Striking red varieties brighten up salads
Image: Spring Onion 'Apache' from Thompson & Morgan

Spring onions add interest to many dishes. The white bulbs have a delicate oniony flavour while the long hollow leaves can be thinly sliced to add texture and colour.

The benefit to growing your own spring onions from seed is that you can try varieties not readily available in the supermarket. Choose from solid all-rounders or those best suited to pickling or growing over the winter. Here are some of our favourites:

• Spring Onion 'White Lisbon' - Short cropping time and great for overwintering, this is a great choice for new gardeners.
• Spring Onion 'Pompeii' - A rounder shape, this silver skinned and succulent variety is ideal for pickling and serving on cocktail sticks.
• Spring Onion 'Apache' - A red variety that offers good flavour and a crisp texture, this spring onion adds interest and colour to salads.
• Spring Onion 'Feast F1 Hybrid' - An outstanding all-rounder ideal for successive sowings to be havested all summer long.

When to sow spring onions

Sow at regular intervals for a succession of spring onions throughout the summer
Image: Spring Onion 'Feast' from Thompson & Morgan

Sow spring onion seeds from March to August at 3 weekly intervals. Harvesting can usually start 8 weeks after sowing.

For an early spring crop, sow seeds in September and over winter.

How to sow and grow spring onions

Sow your seeds thinly in shallow drills
Image: Piotr Debowski/Shutterstock

Spring onions will grow in any good fertile soil provided it’s well drained. Prepare the ground in advance by getting your soil down to a fine tilth and adding a granular general purpose fertiliser about a week before you expect to sow.

Make drills 1.5cm (0.5") deep and 15cm (6") apart and sow thinly. You won’t need to thin your spring onions because you’ll be pulling them and adding them to your salads in just a few weeks.

Spring onions rot in waterlogged soil, so do plant them in well-drained ground, and be careful not to over-water. It’s also crucial to keep weeds away because like all onions, spring onions hate competition. It’s also advisable to protect the young seedlings from birds, by covering them with horticultural fleece.

You can also sow spring onions into containers or pots on the windowsill. Just add compost to within about 3 cm (1") from the top of the container before lightly scattering seed over the surface and covering with 1.5cm (0.5") of compost. Water sparingly to keep the soil moist and you’ll soon have a tasty crop to enjoy.

Tips for growing spring onions

Some varieties grow into large onions if you wait too long to harvest
Image: Shutterstock

Small bulbs are ideal for salads and stir-fries, but some varieties develop into larger, normal-sized onions if you leave them long enough. Do beware of "bolting" in hot weather – snip out any flowering heads as soon as they appear or, though still edible, your onions will be smaller.

Spring onions also overwinter well. By sowing them in late August, through to October you’ll get a nice early crop of crisp salad veg by the end of spring.

Now you know how to grow spring onions, why not give them a go? Versatile, delicious, and highly nutritious, these crisp, crunchy scallions really are a must for your garden. Find more information about onions, garlic and shallots - including grower guides and our full range of products at our hub page.