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Herb
Thai basil
Ocimum basilicum var. thyrsiflora · also Horapha, Anise basil
A basil with purple stems and an aniseed flavour for Thai and Vietnamese cooking. It handles heat and humidity better than sweet basil and is slower to bolt. Grow it year round in the tropics and through the warm months in the subtropics and the south. Frost kills it.
- SunFull sun
- Spacing30 cm apart
- First pick7–10 weeks
- FrostFrost tender
- HeatHandles heat well
- Sow depth2 mm
When to plant where you live
Checking your area…
Add thai basil to my gardenVarieties (1)
- Siam QueenCompact, strongly flavoured Thai basil with purple flower heads
Neighbours
Grows well with
From seed to plate
Plant
30 cm apart, seed 2 mm deep. Full sun.
Water
Regular; keep moist but well drained.
Feed
Liquid feed every few weeks.
Pick, from about 7 weeks
Pick tips often; remove flower buds.
Good to know
- Sow small batches through summer for a steady supply
- Grows well in pots near the kitchen
- Use the leaves fresh; they lose flavour when dried
Common problems
- Goes to flower and woodypinch out buds and harvest tips weekly
- Blackens in coldplant out only once nights stay above about 12 °C
- Aphids, slugs and snailshose off aphids; hand pick snails at night
If you use a garden chemical, follow the label exactly. Try organic options first, and ask the community or Plant Doctor if you're unsure.
Wildlife
Good for: bees.
Where this information comes from
- The Seed Collection: Basil, Thai (growing, medium confidence, checked 29 Oct 2026)
- ASPCA Animal Poison Control: Basil (Ocimum basilicum), non-toxic to dogs and cats (toxicity, high confidence, checked 29 Oct 2026)
Reviewed by AI cross-check (Claude), not a horticulturist on 29 Oct 2026. Version 1.