Growing your own spring onions is much cheaper than buying them at the supermarket.
Spring onions are not only useful in the kitchen to add flavor and texture to stir-fries and salads, but they are also a wonderful filler crop in vegetable beds and pots. They need little space and are happy to grow alongside other vegetables so pop in some seedlings whenever you’ve got a gap left after harvesting something else.
Sow and grow
- Sow seeds: August to April in warm areas; September to March in cool areas
- Transplant: August to April in warm areas; October to March in cool areas
- Position: Full sun
- Harvest: 8-12 weeks
- Good for pots
- Good for beginners
Spring onion seed can be sown directly from late winter until mid-autumn in warmer places and early spring through to early autumn in cooler regions, provided soil is not waterlogged. You can also start indoors in trays or punnets year round, but direct sowing is less trouble and avoids the extra work of transplanting.
In warmer regions you plant spring onion seedlings from late winter until mid-autumn, in cooler regions plant from late spring until early autumn.
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* How to grow chives
Step by step
- If you are sowing directly, make a shallow trench, about 5 mm deep, with your fingertip. Sow seeds along the trench, cover them with a thin layer of soil.
- You could also sow pinches of seed in clumps.
- Seedlings should emerge in 10-14 days.
- When the seedlings appear, thin them out so they are about 10 cm apart. If growing in a clump, picking out two or three of the smallest ones will give the others more room to grow. Don’t waste the thinnings – transplant somewhere else in the garden or snip them up and use them just like chives.
- In a pot, you can space as closely as 5 cm apart.
- When transplanting seedlings, make sure to put the small bulb and roots below the soil, leaving the green stem and any foliage sticking up.
Spring onions do best in fertile, well-worked soil. Before planting, dig in compost or sheep pellets. Water well before and after planting, and continue to water regularly, especially if the summer is dry or you are growing them in pots.
Keep the area around them free of weeds, and if it gets too hot and dry in summer, apply mulch.
To pick, cut the plant off just above soil level, rather than harvesting the whole plant and a new spring onion will likely grow again on the roots left behind.
‘White Lisbon’ is the old favorite and arguably the most popular variety in New Zealand. It is a hardy and reliable grower featuring long white stems and bright green tops.
‘Galloper’ is also a fast grower, forming long, tender white shanks. Hardy in most seasons.
‘Long White’ and ‘White Bunching’ are both impressively easy to grow.
‘Ishikura’ is an open pollinated variety with tall white stems that produce almost no bulb at their base. It has a mild flavor.
Clumping onions (which grow in clusters) are not quite the same as spring onions but grow well under the same conditions. They can be hard-to-find but are fun to grow: look out for ‘Multiplying’, ‘Welsh Bunching’, ‘Bunching’ or ‘Egyptian Walking Onions’.
And remember, in a pinch the green tops of most ordinary bulb forming onions can be used as a spring onion substitute!
High temperature and/or drought stress makes spring onions susceptible to aphid attack, or they simply stop growing. Mulching and deep, targeted watering can help significantly in preventing an infestation, as can sowing in succession, and picking or harvesting them quickly as they grow.
If little black onion aphids take up residence on your spring onions, take action as soon as you spot them. Wash aphids off with the hose or run your fingers along the leaves squashing as you go.