How to grow basil
Overview
Basil is a fast-growing annual herb prized for its aromatic leaves, used fresh in cooking. It thrives in warm weather and needs regular harvesting to stay productive.
Varieties
- Sweet Basil — The classic culinary variety with large, tender leaves, ideal for pesto and salads.
- Thai Basil — Anise-scented with purple stems, essential for Asian dishes and stir-fries.
- Lemon Basil — Citrusy aroma, perfect for fish and salads, grows well in warm climates.
Soil Preparation
Basil prefers slightly acidic to neutral soil (pH 6.0-7.0) with good drainage. Enrich with well-rotted manure or compost before planting. Avoid heavy clay that stays wet.
Growing Guide
Plant basil in well-drained soil enriched with compost, in full sun. Sow seeds 5mm deep, 20cm apart, or transplant seedlings 30cm apart. Water at the base to avoid leaf wetness. Pinch out early flowers to extend leaf production.
Sowing
Sow basil seeds 5mm deep in seed trays or direct in garden after frost. Germination takes 5-10 days at 20-25°C. Transplant when 10cm tall, spacing 30cm apart.
Care
Feed basil every 2-3 weeks with a balanced liquid fertiliser. Pinch out flower buds as they appear to delay bolting. Prune regularly by taking top stems to keep plants bushy and productive.
Companion Planting
Basil grows well with tomatoes, capsicum, and asparagus, repelling some pests. Avoid planting near sage or rue, which may inhibit growth.
Common Pests & Risks
Aphids and whitefly can attack basil; spray with neem oil or soapy water. Downy mildew appears in humid conditions; improve air circulation and avoid overhead watering.
Harvesting
Harvest basil by picking the top leaves and stems once the plant has 6-8 leaf pairs, starting from the top. Regular picking encourages bushier growth and delays flowering.
In the Kitchen
Use basil fresh in salads, pesto, or as a garnish. Add leaves at the end of cooking to preserve flavour. Store in a jar of water on the bench or freeze in oil.
Troubleshooting
Yellow leaves: overwatering or poor drainage, reduce water. Brown edges: underwatering or sunburn, increase water. Leggy growth: not enough light, move to sunnier spot. Flowering early: stress or heat, pinch off buds. Downy mildew: humid air, space plants and avoid wet leaves.