How to grow Spring Onion in New Zealand
Spring onions are quick, mild onions harvested young for their green tops and small white stems, ready in a couple of months rather than the five or more that bulb onions take. They grow year round in the warm north, and in spring and autumn almost everywhere. Sow a short row every three or four weeks for a constant supply.
📖 Our full guide: How to Grow Spring Onions in NZ: When to Sow and Harvest
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | August to April | |
| Auckland | August to April | |
| Waikato & Bay of Plenty | August to April | |
| Central North Island | August to April | |
| Wellington & Lower North Island | August to April | |
| Nelson & Marlborough | August to April | |
| Canterbury | August to April | |
| Otago & Southland | August to March | Sow Aug to Mar. Cover early sowings with a cloche or frost cloth, as frosts run to late October. Get the last sowing in by Mar so it sizes up before winter growth stops. |
| Central Otago | September to March | Start spring sowings in Sep; the soil is too cold before then. Make the last sowing in Mar so the crop is ready before winter growth stops. |
Not to be confused with: Bulb onions, which are left to swell and store, chives, a perennial herb with thin hollow leaves, and leeks.
Where to plant
Spring onions need full sun and well-cultivated, fertile soil enriched with compost and sheep pellets. They are slim and quick, so they fit between slower crops and in pots.
- Northland, Auckland and other warm districts: sow at almost any time of year.
- Canterbury and the central North Island: sow from late winter to autumn.
- Otago and Southland: sow from August to March, covering early sowings with a cloche, as frosts run to late October.
- Central Otago: start spring sowings in September and make the last sowing in March.
Choosing a variety
- Ishikura and Tokyo Long White are Japanese bunching onions with long, straight white stems that do not form bulbs.
- Red bunching types have red-flushed stems and add colour to salads.
How to plant
- Sow seed thinly in furrows about 6 mm deep and 15 cm apart, or scatter it in a pot, and cover lightly.
- Keep the soil moist until the grassy seedlings are up.
- Once the seedlings are up, in 10 to 14 days, thin them to about 5 cm apart.
- Sow again every three to four weeks for a continuous supply.
Watering and feeding
Keep the soil moist, as spring onions have shallow roots. Feed every four weeks during active growth with a vegetable fertiliser, or more often with a liquid feed, for plenty of leafy tops.
Pruning and care through the year
- Keep the rows weeded, as the thin seedlings are easily smothered.
- Mulch lightly to hold moisture.
- Watch for thrips in warm, dry weather.
Harvesting
Start pulling when the stems are pencil thick, usually two to three months after sowing. Or snip them at the base and leave the roots in the ground: they regrow within weeks for a cut-and-come-again harvest. Both the green tops and white stems are eaten raw or cooked.
Growing in pots
Spring onions are one of the easiest crops for pots, troughs and window boxes. Use a quality potting or vegetable mix, sow thinly, keep moist and feed regularly.
Regrowing from the shop
The white root ends of shop-bought spring onions regrow if planted in soil or stood in a little water on a sunny windowsill, giving a few extra harvests of green tops.
Companion planting
Spring onions take little space and fit between many crops.
Good companions
- Carrot A traditional pairing; the two are sown in alternate rows.
- Lettuce Quick crops that share a bed and are picked over a similar time.
- Tomato Spring onions fit around the base of tomato plants.
Keep apart
Avoid planting these close to spring onion.
Pests and diseases
Spring onions have few problems, as they are harvested young.
Pests to watch for
- Thrips Silvery streaks and speckles on the leaves in warm, dry weather.
Diseases to watch for
- Downy mildew Pale, oval patches on leaves with grey-purple fuzz in cool, damp weather.
- White rot Yellowing, wilting plants with white fluffy growth at the base. Do not grow onion-family crops in that soil for many years.
Common questions
How long do spring onions take to grow?
About two to three months from sowing, around half the time of bulb onions.
Will spring onions regrow after cutting?
Yes. Snip them at the base and leave the roots in the ground, and they regrow within a few weeks.
When can I sow spring onions in New Zealand?
In spring and autumn almost everywhere, and year round in the warm north. Choose your region at the top of the page for the months.
Can I grow spring onions in a pot?
Yes. They are one of the easiest crops for pots and window boxes, as long as the mix stays moist.
What is the difference between spring onions and bulb onions?
Spring onions are harvested young for their green tops and slim stems, while bulb onions are left to grow for months to form a large bulb that stores.
Sources we checked: Tui: Spring onion growing guide; Yates NZ: How to grow spring onion; Kings Seeds: Spring onion Ishikura.