How to grow zucchini
Overview
Zucchini (Cucurbita pepo) is a warm-season summer squash grown for its prolific, tender fruit. It is a fast-growing, bushy plant that produces best when planted in full sun with rich, well-drained soil and consistent moisture.
Varieties
- Black Beauty — Classic dark green, high-yielding, reliable in all Australian zones.
- Golden — Bright yellow fruit, sweeter flavour, good for warm climates.
- Lebanese — Pale green, tender, ideal for quick harvests in subtropical gardens.
Soil Preparation
Zucchini prefers a pH of 6.0–6.8. Enrich soil with well-rotted manure or compost before planting. Ensure good drainage to prevent root rot; raised beds help in heavy clay.
Growing Guide
Sow seeds directly 2 cm deep, 60 cm apart, or transplant seedlings at the same spacing after frost. Choose a sunny, sheltered spot with rich, free-draining soil. Water deeply twice a week, increasing to daily in hot weather. Mulch heavily to retain moisture and suppress weeds. Avoid overhead watering to reduce powdery mildew.
Sowing
Sow seeds 2 cm deep, 60 cm apart, directly in the garden after frost. Germination takes 5–10 days in warm soil (20–30°C). Start indoors 3–4 weeks before transplanting in cooler zones.
Care
Feed every 2–3 weeks with a balanced liquid fertiliser once fruiting begins. Prune off older leaves to improve airflow and reduce powdery mildew risk. Mulch around the base to retain moisture and suppress weeds.
Companion Planting
Plant with corn, beans, and nasturtium to deter pests and improve pollination. Avoid planting near potatoes or other cucurbits to reduce disease pressure.
Common Pests & Risks
Powdery mildew is common in humid conditions; improve airflow and apply a milk spray (1:9 milk to water). Aphids and mites can be controlled with a strong water spray or insecticidal soap. Cucumber beetles may damage young plants; use row covers early.
Harvesting
Harvest zucchini when 15–20 cm long, cutting the stem with a knife. Pick every 2–3 days to encourage continued production. Overgrown fruit left on the plant will slow flowering.
In the Kitchen
Harvest young for tender skin and few seeds. Use raw in salads, grilled, or sautéed. Store in the fridge for up to a week; excess can be frozen after blanching.
Troubleshooting
Yellow leaves: overwatering or nitrogen deficiency; reduce water and feed. Brown edges: underwatering or heat stress; increase mulch and water. Powdery mildew: white spots on leaves; improve airflow and apply milk spray. Fruit rot: poor pollination or calcium deficiency; hand-pollinate and add lime. Stunted growth: cold soil or pests; wait for warmth and use row covers.