How to Grow Courgettes (Zucchini) in New Zealand: When to Plant

Updated October 2026

Zucchini (the same plant most New Zealanders call courgette, as the British and French do) is one of the most productive crops you can grow. Sow direct from October once frost has passed in the warm north, or raise seedlings inside in cooler regions. One or two plants is usually plenty. Pick young and often to keep them producing, and water at the base to keep powdery mildew at bay.

What it looks like as it grows

🌱 Plant profile: Zucchini, with sowing times for your region, companion plants and common pests.

Position and soil

Zucchini wants full sun and rich, well-fed soil. It is a hungry, thirsty plant. Dig in plenty of compost and aged manure before planting so the bed holds moisture and feeds the plant through a long season. Good drainage matters too, so a raised mound or bed suits it well.

When to Plant Courgettes in Your Region

Timing matters here, where the warm north and the cooler south are weeks apart. Zucchini needs warm soil of around 18 degrees Celsius, so wait until frost has passed.

Courgettes go in from October in the warm north but not until December in the far south. These are the sowing and planting months for each region from our planting data. Each region links to its vegetable planting calendar, and the Zucchini plant page has spacing, companions and care notes for your region.

Sowing and planting

Build a planting mound or hill by mixing compost and aged manure into the soil. Mounds drain well and warm faster in spring. Sow 2 to 3 seeds per mound, around 2 cm deep, and thin to the single strongest seedling once they have a couple of true leaves. Seeds germinate in about 7 days, and plants are ready to harvest in roughly 60 days. In cooler regions, raise seedlings inside 3 to 4 weeks before your last frost and transplant once the weather settles.

Courgettes From Seed or Seedlings

Courgettes are easy from seed. Our plant data puts emergence at about 7 days in soil between 18 and 30°C. Sow two seeds per mound about 2 cm deep and keep the stronger one. Sowing direct suits the warm north, where sowing starts in October.

Seedlings give you a head start where spring is cool or short. You can raise your own inside, as above, or buy punnets, which are widely available in spring. Plant them out in the months the table shows for your region.

Planting courgette seedlings

1. Build a mound of soil mixed with compost and aged manure in full sun, allowing 80 to 100 cm between plants.
2. Wait until frost has passed and the soil is warm. Our frost dates page gives the average last frost for your region.
3. Water the punnet first, then ease the seedling out with as much soil around the roots as possible.
4. Plant it at the same depth it sat in the punnet, firm the soil gently and water it in well.
5. Water at the base rather than over the leaves while it settles in, and mulch around the base once it is growing.

Spacing

Give each plant room. Space bush varieties 80 to 100 cm apart, roughly one square metre per plant. They grow into large, sprawling plants, and good spacing keeps air moving through the leaves, which is your first defence against powdery mildew. Climbing types such as Tromboncino can be trained up a trellis to save ground space.

Growing Courgettes in Pots

Courgettes can be grown in a container, but our plant data rates them only partly suited to pots, because a bushy plant needs plenty of root room and steady water. Use a pot of at least 50 cm filled with a rich potting mix, and grow one plant in each pot, since a single plant needs about 80 cm of space in the garden.

A compact bush variety such as Golden suits a pot best. Tromboncino is a vigorous climbing vine and is better trained up a trellis in the ground. Pots dry out quickly in summer, so water deeply at the base whenever the mix starts to dry, keep the leaves dry to limit mildew, and switch to a potassium feed once fruit sets.

Watering and feeding

Zucchini are heavy feeders and need consistent water. Water deeply at the base of the plant, never over the leaves, and keep the soil evenly moist rather than swinging between dry and soaked. Mulch around the base to hold moisture. Feed every two to three weeks with a balanced liquid fertiliser once flowering starts to keep the fruit coming.

Pollination

Zucchini produce separate male and female flowers on the same plant. Male flowers appear first on thin, straight stems. Female flowers have a small swelling, the baby courgette, behind the petals. Bees move pollen from male to female. If a female flower is not pollinated, the small fruit behind it yellows, shrivels at the blossom end, and drops off. This poor fruit set is the most common complaint and is often mistaken for disease.

To hand pollinate, pick a male flower, peel back the petals, and dab the pollen-covered stamen onto the stigma in the centre of a female flower. Do it in the morning when the flowers are freshly open.

How Long Do Courgettes Take to Grow?

Courgettes are quick. Our plant data allows about 60 days from sowing to the first fruit, and seedlings appear in about 7 days. Once a plant starts fruiting it keeps going for as long as you keep picking, until powdery mildew, which is almost guaranteed by late summer, slows it down.

Your sowing date decides when picking starts. An October sowing in the warm north can be picked from around December, while a December sowing in Otago, Southland or Central Otago starts cropping from around February. Staggering two sowings four to six weeks apart, as the tip above suggests, spreads the harvest.

Best zucchini varieties for NZ

Companion planting

Grow zucchini near nasturtium, corn, beans, and marigold. Flowers nearby draw in the bees that pollinate your fruit.

Pests and problems

Powdery mildew

White powder over the leaves is almost guaranteed by late summer. Water at the base, improve airflow with good spacing, and remove the worst leaves. A weekly spray of one part milk to nine parts water can slow it. See our powdery mildew guide.

Fruit rotting at the tip

Tiny fruit that rots and drops at the blossom end is poor pollination, common in cool or wet spells. Hand pollinate with a male flower, or wait for the bees in better weather.

28-spotted ladybird and aphids

The 28-spotted ladybird and its larvae skeletonise leaves into a lacy look; pick them off by hand. Aphids and whitefly cluster on soft growth; hose them off and encourage predators. See our NZ pest and disease guide for organic control.

Harvesting

Pick zucchini young at 15 to 20 cm for the best flavour, and check plants every two days during peak production. Fruit grows fast and can double in size overnight. Leave it too long and you get a marrow: watery, tough-skinned, and full of seeds, which also slows down new fruit. Cut the stem cleanly with a sharp knife rather than pulling.

When to pick courgettes

Pick while the fruit is young and glossy, at around finger to hand length and no more than 15 to 20 cm. Cut it with a short stem attached. A single missed fruit swells fast and slows new fruit forming, so a quick check every two days in summer keeps the plant cropping.

Courgettes keep in the fridge crisper for up to 5 days. For a glut, grate them and freeze them in portions for baking.