Basil (Thai)

How to grow Basil (Thai)

Ocimum basilicum var. thyrsiflora

🌿 Herb 🌱 Grown each year

Aniseed-scented basil with purple stems and flowers, essential for Thai curries and stir-fries. Loves warmth — best on a sunny windowsill.

At a glance: Sow early May to mid June, harvest from late June.

When to sow, plant and harvest

JanFebMarAprMayJunJulAugSepOctNovDec
Sow outdoors
Harvest

Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.

Growing Basil (Thai): what it needs

Light
Full sun · 6+ hours a day
Watering
Keep evenly moist; water pots daily in hot weather
Soil
Fertile, well-drained soil
Spacing
20 cm
Height
40 cm
In pots
Grows well in containers
Feeding
A liquid feed every two weeks for pot-grown plants
Harvest
About 55 days from sowing
Hardiness
USDA zones 10–11
Difficulty
Easy

Step by step

  1. Early May – mid June · 3 weeks after the last spring frost

    Sow Seeds Outdoors

    Sow thinly in shallow drills where they are to grow. Sow on the surface and keep at 20°C.

  2. 5–10 days after “Sow Seeds Indoors” · Mid May

    Check Germination

    Seedlings should appear in 5–10 days. Keep the compost moist. If sown outdoors, thin to 20 cm apart.

  3. 45–66 days after “Check Germination” · Late June – mid July

    Start Harvesting

    Pick regularly — little and often keeps plants bushy. Take a photo for the journal.

  4. 21–35 days after “Start Harvesting” · Mid July – late July

    Pinch Out Flower Buds

    Pinch out the flower spikes (or use them — they are edible) so the plant keeps making leaves.

  5. Mid October – early November · around the first autumn frost

    End of Season

    When plants run to seed or the frost gets them, pull them up for compost — leave a few to self-seed if you like.

More herbs to grow

Photo: Filo gèn' / Wikimedia Commons (CC BY-SA 4.0)