Thai basil Ocimum basilicum var. thyrsiflora
Thai basil (Ocimum basilicum var. thyrsiflora) is an annual herb in the Lamiaceae family. It grows 40–60 cm (16–24 in) tall and 30–40 cm (12–16 in) wide, wants full sun and moderate water, and is hardy to about 8 °C (46 °F). Space plants about 30 cm (12 in) apart.
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Thai basil at a glance
| Type | Annual herb |
|---|---|
| Family | Lamiaceae |
| Mature height | 40–60 cm (16–24 in) |
| Mature spread | 30–40 cm (12–16 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Cold hardiness | About 8 °C (46 °F) once established (roughly USDA zone 11) |
| Heat stress | Likely above about 38 °C (100 °F) |
| Flowering | about 7–11 weeks after planting, for 4–9 weeks |
| Days to maturity | About 60 days from planting |
| Wind tolerance | None |
| Pollinator value | High |
| Edible | Yes: leaves, flowers |
| Common in gardens of | 🇹🇭 Thailand, 🇸🇬 Singapore, 🇺🇸 United States, 🇻🇳 Vietnam |
Is Thai basil toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Basil is non-toxic to people and pets.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Thai basil
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
Questions about Thai basil
- How far apart should I plant Thai basil?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–40 cm (12–16 in).
- Does Thai basil need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Thai basil need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Thai basil?
- It tolerates about 8 °C (46 °F) once established, roughly USDA zone 11. As an annual it is usually planted out after the last frost.
- When does Thai basil flower?
- About 7–11 weeks after planting, for 4–9 weeks.
- Is Thai basil poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Basil is non-toxic to people and pets.
- What grows well with Thai basil?
- There is no well-documented companion pairing for Thai basil. Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
- FAO Irrigation and Drainage Paper 56 — Crop Evapotranspiration, FAO
- RHS Plant Finder, Royal Horticultural Society
- University extension gardening guides (general), Various land-grant university extensions
Notes and assumptions
- Typical garden-cultivar values; varieties differ.
- Tolerates tropical heat better than sweet basil.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Basil Ocimum basilicum
- Rosemary Salvia rosmarinus
- Thyme Thymus vulgaris
- Mint Mentha spicata
- English lavender Lavandula angustifolia
- Creeping thyme Thymus serpyllum
- Common sage Salvia officinalis
- Oregano Origanum vulgare