herb
EdibleThai Basil
Ocimum basilicum var. thyrsiflora
Considered non-toxic to cats and dogs (source: ASPCA (basil, non-toxic)).
A sunny south-facing window with 6+ hours, or a grow light.
Keep evenly moist — water when the top inch of soil is dry.
Forgiving and beginner-friendly.
Thai basil has purple stems and an anise edge that holds up in cooked dishes where sweet basil fades. It grows the same easy way: warmth, water, and the brightest spot you can offer.
About Thai Basil
Thai basil (Ocimum basilicum var. thyrsiflora) is the purple-stemmed, anise-scented basil that holds its flavour in cooked dishes where sweet basil fades. It is central to Thai, Vietnamese, and Lao cooking, from stir-fries to the herbs heaped beside a bowl of pho. It grows the same easy way as sweet basil, so a renter needs only a 4-litre pot and the brightest spot available, with a grow light to fall back on.
The care is familiar. Pinch the tips to keep it bushy and slow it from running to flower, and give it warmth and strong light. It takes a little more heat than sweet basil but wants the same steady water. A first harvest lands around 50 to 70 days from sowing, and cutting sprigs from the top keeps new growth coming.
What it’s like to grow
Thai basil is forgiving and tells you when it is unhappy. Leggy, stretched stems point to weak light, while drooping or yellowing lower leaves follow cold or soggy soil. Keep it bright and above about 18 °C and it produces through the warm months. It is non-toxic to cats and dogs, so there is no concern about a curious pet near the pot.
What to expect
First harvest in about 50–70 days. It’s forgiving, so it’s a good one to learn on. No sunny window? It also does fine under a clip-on grow light.
See what you’ll need to get started ↓♻ Regrow from scraps
Root a 10 cm cut stem in a glass of water for one to two weeks, then pot it up.
Companions
Tips
- Pinch the tips to keep it bushy and slow down flowering.
- It tolerates more heat than sweet basil, but still wants strong light.
- Cut sprigs from the top as you need them.
Common problems
- Leggy growth in low light.
- Drooping or yellowing from cold or soggy soil.
Common questions
Is Thai Basil toxic to cats and dogs?
Thai Basil is non-toxic to cats and dogs, which makes it a safe pick if you have pets. Source: ASPCA (basil, non-toxic).
How much light does Thai Basil need?
Thai Basil wants bright light — a south-facing window with six or more hours of sun, or a grow light to make up for it.
How often should I water Thai Basil?
Water Thai Basil when the top inch of soil feels dry, then let it drain. Aim for evenly moist, not soggy.
What temperature does Thai Basil need?
Thai Basil is happiest around 18–32 °C. It tolerates brief dips to about 10 °C, but cold drafts and sudden chills set it back.
How long does Thai Basil take to grow?
Expect a first harvest about 50–70 days from sowing under good conditions. One healthy plant supplies regular sprigs for stir-fries, pho, and curries through the warm months.
Can I grow Thai Basil without a sunny window?
Yes. Thai Basil does well under an affordable clip-on grow light, so a bright window isn't essential.
How big does Thai Basil get?
A bushy upright herb ~0.3–0.5 m tall with purple stems; one plant per small pot.
How do I propagate Thai Basil?
Root a 10 cm stem cutting in water for one to two weeks, then pot up; or sow seed.
What pests affect Thai Basil?
Watch for aphids, whitefly, spider mites and thrips. Check new growth and the undersides of leaves often, and treat early with a rinse or insecticidal soap before they spread.
Is Thai Basil easy to grow?
Yes. Thai Basil is forgiving and one of the better plants to learn on.
Gear for Thai Basil
Gear suggestions to get you started — general picks, not paid placements.
Pet-toxicity from the ASPCA. Care details are general guidance, not professional or veterinary advice; only eat plants you can positively identify as the edible plant and part described. Photo: Katharva, CC BY 3.0, via Wikimedia Commons (CC-BY). Care info last updated 2026-06-08.