Thai Sweet Basil

Family: Lamiaceae Herb

Planting Schedule

Provide your location or planting zone to unlock dates and add Thai Sweet Basil to a garden.

Aromatic and intensely sweet from the first pinch—Thai Sweet Basil fills the garden with a fragrant, anise-citrus perfume and delivers tender leaves with a crisp, slightly succulent bite.

The foliage is lush and upright, producing abundant, narrow leaves that hold their character for fresh use and are especially prized for bold, fragrant flavor in stir-fry style cooking and quick sauces. Grow Thai Sweet Basil for a steady harvest over the season, and enjoy its signature lift in every aromatic application.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Thai Sweet Basil

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Thai Sweet Basil Planting Dates by USDA Zone

Estimated US hardiness-zone windows for sow, transplant, and harvest. Enter a US ZIP above for exact local dates, or open a zone below.

Zone	Start Indoors	Sow / Transplant	Harvest
Zone 1a	Protected Environment Only
Zone 1b	Apr 27th	Jul 20th	Sep 18th – Aug 1st
Zone 2a	Apr 20th	Jul 13th	Sep 11th – Aug 29th
Zone 2b	Apr 10th	Jul 3rd	Sep 1st – Aug 25th
Zone 3a	Apr 10th	Jul 3rd	Sep 1st – Sep 1st
Zone 3b	Apr 14th	Jul 7th	Sep 5th – Sep 21st
Zone 4a	Apr 10th	Jul 3rd	Sep 1st – Sep 24th
Zone 4b	Apr 8th	Jul 1st	Aug 30th – Sep 27th
Zone 5a	Apr 3rd	Jun 26th	Aug 25th – Sep 30th
Zone 5b	Mar 30th	Jun 22nd	Aug 21st – Oct 5th
Zone 6a	Mar 27th	Jun 19th	Aug 18th – Oct 10th
Zone 6b	Mar 21st	Jun 13th	Aug 12th – Oct 16th
Zone 7a	Mar 16th	Jun 8th	Aug 7th – Oct 20th
Zone 7b	Mar 6th	May 29th	Jul 28th – Oct 28th
Zone 8a	Feb 25th	May 20th	Jul 19th – Nov 5th
Zone 8b	Feb 16th	May 11th	Jul 10th – Nov 12th
Zone 9a	Jan 30th	Apr 24th	Jun 23rd – Nov 26th
Zone 9b	Jan 5th	Mar 30th	May 29th – Dec 9th
Zone 10a	—	Oct 1st	Nov 30th – Feb 28th
Zone 10b	—	Oct 1st	Nov 30th – Feb 28th
Zone 11a	—	Oct 1st	Nov 30th – Feb 28th
Zone 11b	—	Oct 1st	Nov 30th – Feb 28th
Zone 12a	—	Oct 1st	Nov 30th – Feb 28th
Zone 12b	—	Oct 1st	Nov 30th – Feb 28th
Zone 13a	—	Oct 1st	Nov 30th – Feb 28th
Zone 13b	—	Oct 1st	Nov 30th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	60
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	60
Min Night Temp (°F)	50
Harden Off (days)	10

Culinary Notes

Chef's Note

Thai Sweet Basil isn’t just “basil with a different name”—its anise-citrus aroma makes it the fragrant engine of high-heat cooking, where you want leaves to stay lively and a little snappy. Keep it off long simmering and fold it in late; the flavor stays bright and incense-like rather than turning leafy-bitter.

Best Uses

quick stir-fries where the leaves stay vibrant instead of collapsing
no-cook or barely-heated sauces (tear in off-heat) for maximum perfume
Thai-style basil chicken/pork or sausage stir-fries where it works like a fragrant finishing herb
fresh leaf garnish on noodles or fried rice, added at the last minute so it doesn’t go bitter

Flavor Profile

intensely aromatic sweet basil with anise-citrus lift cool, peppery-herbal bite tender, narrow leaves with a crisp-succulent crunch

Kitchen Pairings

garlic fish sauce lime juice chili soy sauce chicken or pork

Frequently Asked Questions

What pest or disease most often hits Ocimum basilicum (Thai sweet basil), and how do I stop it?

Watch for downy mildew and leaf-spot issues, especially in warm, humid weather with wet foliage. Improve airflow by thinning crowded plants and water at the soil line (not the leaves), then remove any heavily spotted leaves. If problems spread, apply a labeled fungicide for basil downy mildew/leaf-spot according to the product directions, and avoid harvesting or working plants when foliage is wet.

How often should I water Thai sweet basil during peak growth so it stays productive?

During the main growth phase, keep the root zone evenly moist but not soggy—water when the top 1 inch of soil feels dry. Expect roughly 1–2 deep waterings per week in typical summer conditions, increasing frequency during hot, windy spells. Consistent moisture prevents bitter leaves and helps basil keep pushing tender new growth.

How can I tell when Thai sweet basil is ready to harvest?

Harvest when plants are about 8–12 inches tall and have developed multiple sets of mature leaves, typically around 60 days from sowing (often sooner if conditions are ideal). Pick by snipping above a leaf pair to encourage branching, and start with frequent light harvests rather than stripping the plant once. Stop major harvesting when flowering begins, since leaf size and flavor shift as Ocimum basilicum transitions to bloom.