Herb guide

Thai Basil

Ocimum basilicum var. thyrsiflora · Annual

Sturdier and more anise-scented than sweet basil, and grown almost identically. Propagates readily from cuttings.

What it needs indoors

Light
Full sunAt least 6 hours direct sun
Water
Keep moistWhen the top of the soil feels dry
Temperature
Above 70°F
Growing medium
Light potting soil or coconut coir
Native range
Mainland Southeast Asia
Difficulty
Beginner

What usually goes wrong

Cutting in the glass goes soft and brown at the cut end instead of rooting

A warm room speeds up rooting and rotting at much the same rate, and in water left to stand the bacteria get there first.

Fix: Change the water every day or two, recut the stem on a clean diagonal above the damage, and strip any leaves sitting below the waterline. Roots normally show inside a fortnight.

Sticky leaves, and clusters of small green insects on the softest tips

Aphids, working the newest growth. Indoors there is nothing eating them.

Fix: Rinse them off under the tap, then check the growing tips twice a week for the next fortnight. One missed cluster restarts the whole thing. Insecticidal soap if rinsing is not holding them.

Wants the same conditions

Grow these alongside Thai Basil and one watering routine will suit them all.