How to Grow Onion in New Zealand
Updated June 2026
A long-haul crop; plant once and wait around six months. Onions are day-length sensitive, so the Pukekohe Long Keeper suits Auckland and the warm north well.
What it looks like as it grows
When to plant onion in New Zealand
Timing is everything in New Zealand, where the warm north and the cooler south are weeks apart. Sow or plant in these months for your region:
| Region | When to sow or plant |
|---|---|
| Northland | March, April, May, June |
| Auckland | March, April, May, June |
| Waikato & BoP | March, April, May, June |
| Wellington | March, April, May, June |
| Nelson & Marlborough | March, April, May, June |
| Canterbury | March, April, May, June |
| Otago & Southland | March, April, May, June |
| Central Otago | March, April, May, June |
Best onion varieties for NZ
- Pukekohe Long Keeper, The NZ market standard; high-yielding brown onion that stores for months. (Kings Seeds, Yates NZ, Mitre 10)
- Yellow Sweet Spanish, Large, mild golden onions; best used fresh rather than long storage. (Kings Seeds)
- Red Long Keeper, Deep-red storing onion with a sweet, mild flavour. (Kings Seeds, Egmont Seeds)
How to grow onion
- Space plants about 10cm apart.
- Sow seed around 1.5cm deep.
- Position: full sun.
- Ready to harvest in roughly 180 days.
- Seeds germinate in about 12 days.
Companion planting
Grow onion near: Carrot, Beetroot, Lettuce, Silverbeet, Chamomile.
Pests and problems
Watch for: Thrips. See our NZ pest and disease guide for organic control.
When it goes wrong
The most common ways onion trips people up, and what to change next time:
Bulbs stay small
Crowding, weeds, or sown at the wrong time. Give them room, keep weed-free, and plant for your day length and region.
Plants run up to flower
Bolting from a cold snap after planting. Plant at the right time and avoid very large seedlings.
Rot in storage
Lifted too wet or necks not dried. Cure them in a dry airy spot until the necks are papery.
🌱 Plant Onion in your garden →FAQ
When is the best time to plant onion in New Zealand?
In the warm north (Auckland, Northland) sow in March, April, May, June. Cooler regions plant a little later. Check the table above for your region.
Where can I buy onion seeds or plants in NZ?
Try Kings Seeds, Yates NZ, Mitre 10.