Basil — How to Grow Basil in Australia

☀️ Sun

Full Sun

💧 Water

Medium

↔ Spacing

30cm apart

↕ Height

Up to 50cm

📅 Harvest

60 days

Growing Guide

Basil is a warm-season herb that demands attention to timing in Australian gardens. Plant seedlings or direct sow seeds in spring (September–November) once all frost risk has passed and soil temperatures consistently reach at least 18°C. In subtropical regions, planting can extend into early summer (December). Avoid planting during winter (June–August) in temperate and Mediterranean zones, as cold snaps will stunt or kill the plant.

1. Soil Preparation: Basil thrives in well-draining, fertile soil with a pH of 6.0–7.0. Enrich garden beds with compost and aged manure before planting to boost organic matter.

2. Planting: Sow seeds 5 mm deep or transplant seedlings 30 cm apart in a warm, sheltered spot receiving full sun for at least 6–8 hours daily.

3. Watering: Water consistently at the base of the plant, keeping soil evenly moist but never waterlogged. Allow the top 2 cm of soil to dry slightly between waterings. Avoid wetting foliage to prevent fungal issues.

4. Feeding: Apply a balanced liquid fertiliser every two to three weeks during the growing season.

5. Harvesting: Begin harvesting once plants have at least six sets of leaves. Pinch stems just above a leaf node to encourage bushy regrowth. Harvest frequently to delay flowering and extend leaf production.

🤝 Good Companions

Basil grows exceptionally well alongside tomatoes capsicum and parsley as it is believed to enhance their flavour while helping to repel aphids and whiteflies. Planting basil near marigolds creates a powerful pest-deterrent combination that protects the broader vegetable garden.

❌ Avoid Planting With

Avoid planting basil near sage or common thyme as these herbs prefer drier soil conditions that are incompatible with basil's moisture requirements leading to stress for one or both plants. Fennel is also a poor companion as it releases allelopathic compounds that can inhibit basil's growth.

🐛 Pests & Diseases

In Australian gardens, basil is most commonly troubled by aphids, slugs, and caterpillars, which can be controlled by hand-picking, applying food-grade diatomaceous earth around the base, or using a diluted neem oil spray. Fungal diseases such as downy mildew and fusarium wilt can develop in humid conditions — improve airflow between plants and avoid overhead watering to minimise risk. If downy mildew appears, remove affected foliage immediately and apply a copper-based organic fungicide.

🌱 Fertilising

Feed basil every two to three weeks throughout the growing season with a balanced liquid fertiliser such as fish emulsion or seaweed solution, both of which are widely available across Australia and support lush, flavourful leaf growth. Avoid high-nitrogen synthetic fertilisers in excess, as they can promote rapid but flavourless growth; organic options deliver steady nutrients that maintain aromatic oil concentration.

✂️ Pruning & Training

Begin pruning basil once it reaches 15–20 cm tall by pinching out the central growing tip just above a pair of leaves, which encourages the plant to branch out and produce a fuller, bushier shape. Remove flower spikes (bolting stems) as soon as they appear to redirect the plant's energy back into leaf production and significantly extend your harvest season.

🔬 Propagation

Basil is most easily propagated from seed, sown directly into warm soil or seed-raising mix from September onwards — seeds germinate reliably within 5–10 days when temperatures are above 18°C. Alternatively, take 10 cm stem cuttings from a healthy plant, strip the lower leaves, and place them in a glass of water on a warm, sunny windowsill until roots develop in one to two weeks before potting on.

🗓 When to Plant

Spring Summer

🌾 Harvest

Spring Summer Autumn

🌏 Australian Climates

Subtropical Temperate Mediterranean

More Herbs

Rosemary → Ginger → Turmeric → Chives → Garlic Chives → Mint →