How to Grow Zucchini in Australia
Updated June 2026
Varieties, planting times, pollination, harvesting, and how to avoid the famous zucchini glut
Zucchini (known as courgette in Britain and France, but zucchini here and in Italy) is the fastest-producing summer vegetable you can grow. Plants go from seed to first harvest in about 8 weeks, and once they start cropping you will be picking fruit every couple of days. A single healthy plant can easily feed a household through summer, which is exactly why so many gardeners end up with more zucchini than they know what to do with.
This guide covers the best zucchini varieties for Australian gardens, when to plant by region, and practical advice on pollination, harvesting, and beating powdery mildew. Start with the calculator below to work out how few plants you actually need.
How many zucchini plants should I grow?
Enter your household size. Zucchini is wildly productive, so the answer is almost always fewer plants than you would guess.
What it looks like as it grows
Position and Soil
Zucchini wants full sun, at least six hours a day, 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. Heavy clay or thin sandy soil both improve with a generous load of organic matter. Good drainage matters too, so raised mounds or beds suit zucchini well.
Sowing and Planting
Zucchini needs warm soil to germinate. Wait until soil temperature is consistently 18 to 20 degrees Celsius or above before sowing, which is after your last frost. In cool regions, raise seedlings indoors in pots 3 to 4 weeks before the last frost and transplant once the weather has settled. In warm regions you can sow direct.
Build planting mounds or hills by mixing compost and aged manure into the soil. Mounds improve drainage and warm up faster in spring. Sow 2 to 3 seeds per mound, 2 cm deep, and thin to the single strongest seedling once they have a couple of true leaves.
Spacing
Give each plant room. Space bush varieties 80 to 100 cm apart, which works out to 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 sturdy trellis to save ground space.
Watering and Feeding
Zucchini are heavy feeders and need consistent water. Water deeply at the base of the plant, never over the leaves, and aim to keep the soil evenly moist rather than letting it swing between bone dry and soaked. Uneven watering stresses the plant and can worsen fruit problems. Mulch around the base to hold moisture. Feed every two to three weeks with a balanced liquid fertiliser once the plant starts flowering 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 zucchini, behind the petals. Bees move pollen from male to female flowers.
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 single most common zucchini complaint and is regularly mistaken for disease. In cool, wet, or windy weather bee activity drops and pollination can fail.
To hand pollinate, pick a male flower, peel back the petals, and dab the pollen-covered stamen directly onto the stigma in the centre of a female flower. Do this in the morning when the flowers are freshly open.
Common Problems
Powdery mildew
White powdery patches on the leaves are the most common zucchini problem, especially in late summer. The fungus thrives in warm days, cool nights, and still air. Space plants well, water at the base, and remove badly affected leaves. A weekly spray of one part milk to nine parts water can slow the spread.
Fruit rotting at the tip
Small fruit that yellows and rots at the blossom end is poor pollination, not a disease. See the pollination section above. Planting flowers nearby to draw in bees and hand pollinating in poor weather will fix it.
Twenty-eight spotted ladybird and aphids
The 28-spotted ladybird (a dull orange beetle with many spots) and its larvae skeletonise zucchini leaves, leaving a lacy, dried-out look. Pick them off by hand. Aphids cluster on soft new growth and flower buds; hose them off or squash them, and encourage predators like lacewings and hoverflies by keeping flowers in the garden.
Harvesting
Pick zucchini young at 15 to 20 cm for the best flavour and texture, and check plants every two days during peak production. Fruit grows fast in warm weather and can double in size overnight. Leave it too long and you get a marrow: watery, tough-skinned, and full of seeds. Marrows also drain the plant and slow down new fruit, so picking often is what keeps the harvest going for months. Cut the stem cleanly with a sharp knife or secateurs rather than pulling, which can damage the plant.
Best Zucchini Varieties for Australia
| Variety | Type | Notes |
|---|---|---|
| Black Beauty (Blackjack) | Bush, dark green | The reliable default. Heavy cropper, widely sold at nurseries and hardware stores. Good in every region. |
| Costata Romanesco | Bush, ribbed green | Italian heirloom with deep ribs and a rich, nutty flavour. Also prized for its flowers. |
| Golden (Yellow) | Bush, yellow | Bright yellow fruit, same habit as green types. Easy to spot in the foliage so you miss fewer. |
| Lebanese | Bush, pale green | Tender pale skin, best picked small at 10 to 15 cm. Excellent grilled, stuffed, or raw. |
| Round (Eight Ball / Tondo) | Bush, round | Tennis-ball shaped fruit, ideal for stuffing and roasting whole. A fun choice for kids. |
| Tromboncino | Climbing, long curved | Vigorous climber for a trellis. Firm flesh, few seeds, and better vine-borer resistance than bush types. |
When to Plant by Region
Zucchini is a southern-hemisphere summer crop here, planted into warming soil once frost has passed.
- Cool temperate (Melbourne, Hobart, Canberra): sow October to December, after the last frost.
- Warm and temperate (Sydney, Perth, Adelaide): sow September to January.
- Subtropical (Brisbane, Northern NSW): sow August to February.
- Tropical (Darwin, Far North QLD): plant through the dry season, roughly April to August.
Track Your Zucchini in the App
Add zucchini to your garden in the Planting Season app and get reminders for sowing, transplanting, and harvest, plus a heads-up before the glut arrives.
Open the App →Frequently Asked Questions
How many zucchini plants per person do I need?
Far fewer than most people think. Two to three plants feed most households for the whole summer, no matter how many people are in the family. Even one healthy plant produces a steady supply once it gets going. Zucchini is so productive that planting one extra plant per person almost always leads to a glut.
Why are my zucchini rotting at the end?
Small fruit that yellows and rots at the blossom end before it develops is almost always poor pollination, not a disease. The female flower was not pollinated, so the tiny fruit behind it shrivels and drops off. It is common in cool or wet weather when bee activity is low. Hand pollinate by transferring pollen from a male flower to the centre of a female flower with a small paintbrush or cotton bud.
What can I do with a glut of zucchini?
Grate and freeze it in measured portions for baking, make zucchini relish or pickles, bake zucchini slice or loaf, stuff and roast the larger ones, or spiralise it as a pasta substitute. The best fix is prevention: pick fruit young at 15 to 20 cm every two days and grow only two or three plants.
When should I plant zucchini in Australia?
Plant after the last frost when soil is 18 to 20 degrees Celsius or warmer. In cool-temperate regions (Melbourne, Hobart, Canberra) sow from October to December. In subtropical areas (Brisbane, Northern NSW) sow from August to February. Tropical gardeners (Darwin, Far North QLD) plant through the dry season from April to August.
How much space does a zucchini plant need?
Allow about one square metre per plant. Space bush varieties 80 to 100 cm apart. They grow large and need room for airflow, which also helps prevent powdery mildew. Climbing types like Tromboncino can be trained up a trellis to save ground space.
How do I hand pollinate zucchini?
Identify a male flower (thin straight stem, no swelling behind it) and a female flower (a tiny fruit visible behind the petals). Pick the male flower, peel back the petals, and dab the pollen-covered stamen directly onto the stigma in the centre of the female flower. Do this in the morning when the flowers are freshly open.
Is zucchini the same as courgette?
Yes. Zucchini and courgette are two names for the same plant. Zucchini is the Italian and Australian name, courgette is the French and British name. They are grown and harvested in exactly the same way.
Why are my zucchini turning into marrows?
A marrow is simply a zucchini that was left on the plant too long. Fruit can double in size overnight in warm weather. Pick at 15 to 20 cm and check plants every two days. Oversized fruit is watery and seedy, and it slows down production of new zucchini.
See also: Zucchini in the Plant Library
