Holy basil (tulsi) is a sacred herb in Ayurvedic medicine — the clove-pepper-anise flavour and aroma are distinct from any other basil. Used in Thai cooking, Indian chai teas, and as a daily medicinal herb for immunity, stress, and respiratory support. The purple-stemmed Kapoor variety is the most commonly grown; Krishna (dark purple leaves) and Vana (wild, lighter flavour) are also worth seeking out.
Start from seed indoors; slower to establish than sweet basil but vigorous once growing. The flowers are beautiful and attract pollinators — allow some to bloom and set seed for volunteers next year.
Downy mildew
Yellowing on top of leaves with grey-purple fuzz underneath. Spreads rapidly in humid conditions.
Remove affected leaves. Improve air circulation. Avoid overhead watering. Copper spray as preventive.
Fusarium wilt
Sudden wilting, brown streaks in stems, yellowing leaves. Affects sweet basil varieties most.
No cure. Remove and destroy plants. Do not replant in the same spot for 3+ years. Choose resistant varieties.
Aphids
Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.
Damping Off
Seedlings collapse at the soil line with thin, water-soaked stems; seeds may fail to emerge or rot before sprouting.
Sow in well-draining mix, avoid overwatering, and ensure good airflow. Remove affected seedlings and let the surface dry between waterings.