How to grow Leek in New Zealand
Leeks have the mildest, sweetest flavour of the onion family, and they stand in the ground through winter to be dug as needed for soups, pies and roasts. They take about four to five months, but they are easy: raise seedlings, plant them deep so the stems blanch white, and keep them watered. They are especially good in colder districts, where they seem to taste sweeter.
📖 Our full guide: How to Grow Leek in New Zealand
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | August to October, January to April | |
| Auckland | August to October, January to April | |
| Waikato & Bay of Plenty | August to October, January to April | |
| Central North Island | August to October, January to April | |
| Wellington & Lower North Island | August to October, January to April | |
| Nelson & Marlborough | August to October, January to April | |
| Canterbury | August to April | Sow Aug to Apr. Cover early sowings with a cloche or frost cloth, as frosts run to mid October. Get the last sowing in by Apr so it sizes up before winter growth stops. |
| Otago & Southland | September to January | Start spring sowings in Sep; the soil is too cold before then. Cool summers let you keep sowing through Nov to Dec. Make the last sowing in Jan so the crop is ready before winter growth stops. |
| Central Otago | September to December | Start spring sowings in Sep; the soil is too cold before then. Keep sowing through Nov to Dec with steady watering. Skip autumn sowings; growth stops before they are ready. |
Where to plant
Grow leeks in full sun in deep, well-cultivated soil with plenty of compost and sheep pellets dug in. Leeks are long-term crops, so pick a bed you will not need for several months. If your soil is acid, add lime or dolomite before planting.
They belong to the onion family, so rotate them with onions, garlic and shallots, and keep them out of beds where white rot has occurred.
- Northland, Auckland, Waikato and Bay of Plenty, the central North Island, Wellington, and Nelson and Marlborough: sow from January to April and from August to October.
- Canterbury: sow from August to April. Cover early sowings with a cloche or frost cloth, as frosts run to mid October, and get the last sowing in by April so it sizes up before winter growth stops.
- Otago and Southland: start sowing in September, when the soil has warmed, and keep sowing until January so the crop is ready before winter growth stops.
- Central Otago: sow from September to December with steady watering. Skip autumn sowings, as growth stops before they are ready.
Choosing a variety
| Variety | Notes |
|---|---|
| Musselburgh | A popular, hardy home-garden leek with long, thick white shanks |
| Defiant F1 | A disease-tolerant hybrid with a long shank, mid to late maturing |
| Winter Giant | A hardy type for standing through winter |
| Swiss Zermatt | Very early, with long, slender shanks; good for baby leeks |
How to plant
- Sow seed thinly in trays or a seedbed and keep it moist. Feed seedlings weekly with a liquid fertiliser once they are up.
- Transplant when seedlings are about 10 cm tall and pencil thick, early in the morning or late in the day.
- Make holes about 15 cm deep with a dibber or stick, drop a seedling into each and water it in without filling the hole; the soil settles in over time and blanches the stem.
- Space plants about 15 to 20 cm apart in rows 30 to 50 cm apart.
- Mulch with pea or lucerne straw and water in well.
Watering and feeding
Keep leeks consistently watered, especially through dry spells, so growth does not stall.
Feed every week or two with a liquid vegetable fertiliser, or side-dress with a nitrogen-rich vegetable food, as leeks are hungry, leafy crops.
Pruning and care through the year
- As the leeks grow, draw soil or mulch up around the stems a few times to lengthen the white, blanched part. Keep soil out of the leaf joints, where it is hard to wash out.
- Keep the bed weeded; leeks are slow and do not compete well.
Harvesting
Start lifting leeks once the white shaft is thick enough to use, from about four to five months after sowing. Ease them up with a fork rather than pulling, which can snap them.
Leeks stand well in the ground through winter, so dig them as you need them. In spring they start to form a hard flower stalk, so use them up before then. Leeks keep about two weeks in the fridge, unwrapped.
Growing in pots
Leeks grow in deep pots at least 30 cm wide and deep. Plant seedlings 10 to 20 cm apart and deep, keep the mix moist and feed weekly. Baby leek varieties such as Swiss Zermatt suit pots well.
Companion planting
Leeks are slim and upright and share a bed easily with other cool-season crops.
Good companions
- Carrot A traditional pairing; the strong onion scent may help mask carrots from carrot rust fly.
- Celery Shares the same rich, moist soil and long season.
Keep apart
Avoid planting these close to leek.
- Legumes Traditional advice keeps the onion family away from beans and peas.
Pests and diseases
Leeks have few problems. Rust in humid weather and thrips in dry summers are the most common.
Pests to watch for
- Thrips Silvery, mottled streaks on the leaves in hot, dry weather.
- Slugs Young seedlings chewed after planting out.
Diseases to watch for
Common questions
How do I get long white leeks?
Plant seedlings deep, in holes about 15 cm deep, and draw soil or mulch up around the stems as they grow. The buried part stays white and tender.
When should I sow leeks in New Zealand?
In most of the North Island and the top of the South, from January to April and from August to October. In Canterbury sow from August to April, in Otago and Southland from September to January, and in Central Otago from September to December.
How long do leeks take to grow?
About four to five months from sowing. They then stand in the ground through winter, so you can dig them as needed.
What are the orange spots on my leeks?
That is rust, common in mild, humid weather. Give plants room for airflow, keep them well watered and fed, and remove the worst leaves. The stems are still fine to eat.
Can I grow leeks in a pot?
Yes, in a pot at least 30 cm wide and deep. Plant seedlings deep, keep them moist and feed weekly. Baby leek varieties suit pots best.
Why have my leeks gone to seed?
Leeks naturally flower in spring after winter, and a cold snap or stress can trigger it early. Use them up before they form the hard flower stalk.
Sources we checked: Tui: Leek growing guide; Yates NZ: How to grow leeks.