Thai Basil
Ocimum basilicum var. thyrsiflora
📖 About this plant
Thai Basil (Ocimum basilicum var. thyrsiflora) is a distinctive cultivar of sweet basil prized for its spicy anise-licorice flavour and sturdy texture that holds up well to high-heat cooking. Native to Southeast Asia, it is an essential herb in Thai, Vietnamese, Laotian, and Cambodian cuisines — featuring prominently in green curry, pad kra pao, pho, and stir-fries. Unlike Italian sweet basil, Thai basil has a more pungent, peppery, clove-like flavour with hints of anise, and its leaves remain firm even when cooked, making it ideal for soups, curries, and stir-fries where sweet basil would dissolve. The plant is highly ornamental — its purple stems and flower bracts contrast beautifully with the dark green leaves, making it a stunning addition to herb gardens, vegetable beds, and even flower borders. Thai basil is a staple in Indian cuisine as well, used in chutneys, herbal teas, and as a garnish for Southeast Asian-inspired dishes. The plant is rich in essential oils (estragole, linalool, eugenol) that have antioxidant, anti-inflammatory, and antimicrobial properties. Like other basils, Thai basil attracts bees and butterflies when in flower, making it a beneficial companion plant in vegetable gardens.
🧑🌾 Care requirements
Full sun
Keep soil moist
Moderate (40-70%)
20-35°C
Well-draining loamy soil rich in organic matter; pH 6.0-7.5
Light feeder — balanced fertilizer every 4-6 weeks
🌐 Common Names
📋 Plant facts
- 🌍 Origin
- Southeast Asia
- 📏 Max height
- 30-60 cm
- 📐 Spread
- 30-45 cm
- 🕰️ Bloom time
- Late summer to autumn; pinch off flowers to extend leaf harvest
- 🎨 Bloom color
- Purple-pink flowers in spikes
- 🍃 Foliage color
- Dark green to purple-tinged leaves with spicy anise aroma
- ⏳ Lifespan
- Annual in cold climates; perennial in tropics
- 📈 Growth rate
- Fast — ready to harvest in 60-90 days from seed
- ☠️ Toxicity
- Non-toxic — culinary herb; safe for humans and pets
- 🌱 Propagation
- Seeds (germinate in 5-10 days), stem cuttings root easily in water
🛡️ Health & Safety
Non-toxic — culinary herb; safe for humans and pets
Common issues
- Aphids on new growth
- Japanese beetles
- slugs on young plants
- downy mildew in humid weather
- fusarium wilt (soil-borne)
- leaf spot
- bolting (flowering) triggered by heat or long days
💡 Care tips
- Plant in full sun (6+ hours) for the best flavour and compact growth.
- Pinch off flower spikes as they form to extend leaf production — once the plant flowers, leaf flavour declines.
- Harvest leaves regularly from the top to encourage bushy lateral growth.
- Sow seeds every 3-4 weeks for continuous supply through the season.
- Water at the base (not on leaves) to prevent fungal diseases.
- Thai basil grows exceptionally well in containers — use a 10-12 inch pot with good drainage.
- Pair with tomatoes, peppers, and marigolds in the vegetable garden (companion planting).
- For best flavour, harvest in the morning after dew has dried.
- To preserve, puree leaves with olive oil and freeze in ice cube trays.
- Use fresh in curries, stir-fries, soups, and salads — add at the end of cooking to preserve aroma.