How to grow Collards in New Zealand
Collards, or collard greens, are a loose-leafed member of the cabbage family grown for their big, smooth, blue-green leaves, with a mild cabbage flavour. They handle both heat and cold better than most brassicas, and one plant gives months of picking if you take the lower leaves as you need them. They are grown much like kale.
📖 Our full guide: How to Grow Collards
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| Northland | August to October, January to March | |
| Auckland | August to October, January to March | |
| Waikato & Bay of Plenty | August to October, January to March | |
| Central North Island | August to October, January to March | |
| Wellington & Lower North Island | August to October, January to March | |
| Nelson & Marlborough | August to October, January to March | |
| Canterbury | August to October, January to March | |
| Otago & Southland | September and October, January to March | Sow Sep to Oct and Jan 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 and October, January to March | Sow Sep to Oct and Jan to Mar. Cover early sowings with a cloche or frost cloth, as frosts run to early November. Get the last sowing in by Mar so it sizes up before winter growth stops. |
Not to be confused with: Kale, a close relative also picked leaf by leaf, and Cabbage, which forms a tight head.
Where to plant
Grow collards in full sun in firm, rich, well-drained soil with plenty of compost. As with all brassicas, rotate them around the garden to avoid clubroot.
- Northland, Auckland, Waikato and Bay of Plenty, the central North Island, Wellington, Nelson and Marlborough, and Canterbury: sow from August to October and from January to March.
- Otago and Southland and Central Otago: sow in September and October and from January to March, covering early sowings with a cloche or frost cloth. Get the last sowing in by March.
Choosing a variety
- Georgia Southern: a classic heirloom with big blue-green leaves, slow to bolt and heat tolerant.
- Champion: compact and cold hardy, good for smaller beds.
How to plant
- Sow seed about 6 mm deep in trays of seed raising mix.
- Keep moist; seedlings appear in 5 to 10 days.
- Transplant 30 to 45 cm apart into firm, compost-rich soil.
- Water in and cover with insect mesh straight away against white butterfly and diamondback moth.
Watering and feeding
Water deeply and consistently. Feed every few weeks with a nitrogen-rich fertiliser for steady leaf growth.
Pruning and care through the year
- Keep insect mesh on while white butterfly is active.
- Remove yellowing lower leaves.
- Rotate brassica beds each year.
Harvesting
Pick the lower, outer leaves once they reach about hand size, working up the stem. The plant keeps producing new leaves from the top for a long season. Young leaves are the most tender.
Collards keep 4 to 5 days in a bag in the fridge, and can be blanched and frozen.
Growing in pots
Collards grow well in a pot at least 30 cm wide, in full sun, with rich potting mix kept moist. Feed regularly and cover with insect mesh.
Using it
Slice and braise collards slowly with garlic, onion or bacon, add them to soups and stews, or use young leaves in stir-fries. The large leaves can also be used as wraps.
Companion planting
Aromatic herbs and flowers around collards bring in beneficial insects.
Good companions
- Beetroot A quick root crop that fits between the plants.
- Onion A slim crop that fits between rows.
- Dill Its flowers attract hoverflies and parasitic wasps that prey on caterpillars and aphids.
- Nasturtium Draws aphids and some caterpillars away from the crop.
Keep apart
Avoid planting these close to collards.
- Strawberry Traditionally kept away from cabbage family crops.
- Tomato A summer crop with different needs that shades young brassicas.
Pests and diseases
Caterpillars and aphids are the main problems, and insect mesh prevents most of the damage.
Pests to watch for
- White butterfly Irregular holes in leaves, green caterpillars and droppings.
- Diamondback moth Small green caterpillars that wriggle when touched, and leaves with small holes.
- Aphids Grey, waxy colonies under leaves, with distorted new growth.
- Slugs Ragged holes and slime trails.
Diseases to watch for
- Clubroot Plants wilt on warm days, with swollen, distorted roots. Rotate brassica beds.
- Downy mildew Yellow patches on leaves with grey fuzz underneath in cool, damp weather.
Common questions
What are collards?
A loose-leafed cabbage family vegetable grown for its big, smooth, blue-green leaves, picked a few at a time like kale.
When do I sow collards in New Zealand?
From August to October and January to March in most regions. In Otago, Southland and Central Otago, sow in September and October and January to March.
How do I harvest collards?
Pick the lower outer leaves once they are about hand size, working up the stem. The plant keeps producing from the top for months.
Do collards handle heat?
Better than most brassicas. They tolerate both heat and cold, though they are still best in the cooler seasons.
How do I stop caterpillars on collards?
Cover the plants with fine insect mesh from planting, so white butterflies and diamondback moths cannot lay eggs on them.
Sources we checked: Kings Seeds: Collard Greens; Yates NZ: Common problems of kale.