Thai Sweet

Family: Lamiaceae Herb

Planting Schedule

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

Fragrant as a warm evening garden—Thai Sweet basil releases a bright, sweet-anise perfume with a gentle clove lift as soon as you brush its leaves.

The foliage is tender and lush, with a smooth, medium-fine texture and an aromatic sweetness that makes it a standout for fresh garnishing, fragrant sauces, and quick pickling-style preserves. Grow Thai Sweet for a steady harvest at about 50 days, when plants are vigorous and richly leafed for repeated picking.

Light: Full SunMaturity: 50 DaysHabit: Upright

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Thai Sweet 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 13th	Sep 1st – Aug 1st
Zone 2a	Apr 20th	Jul 6th	Aug 25th – Aug 29th
Zone 2b	Apr 10th	Jun 26th	Aug 15th – Aug 25th
Zone 3a	Apr 10th	Jun 26th	Aug 15th – Sep 1st
Zone 3b	Apr 14th	Jun 30th	Aug 19th – Sep 21st
Zone 4a	Apr 10th	Jun 26th	Aug 15th – Sep 24th
Zone 4b	Apr 8th	Jun 24th	Aug 13th – Sep 27th
Zone 5a	Apr 3rd	Jun 19th	Aug 8th – Sep 30th
Zone 5b	Mar 30th	Jun 15th	Aug 4th – Oct 5th
Zone 6a	Mar 27th	Jun 12th	Aug 1st – Oct 10th
Zone 6b	Mar 21st	Jun 6th	Jul 26th – Oct 16th
Zone 7a	Mar 16th	Jun 1st	Jul 21st – Oct 20th
Zone 7b	Mar 6th	May 22nd	Jul 11th – Oct 28th
Zone 8a	Feb 25th	May 13th	Jul 2nd – Nov 5th
Zone 8b	Feb 16th	May 4th	Jun 23rd – Nov 12th
Zone 9a	Jan 30th	Apr 17th	Jun 6th – Nov 26th
Zone 9b	Jan 5th	Mar 23rd	May 12th – Dec 9th
Zone 10a	Continuous Production
Zone 10b	Continuous Production
Zone 11a	Continuous Production
Zone 11b	Continuous Production
Zone 12a	Continuous Production
Zone 12b	Continuous Production
Zone 13a	Continuous Production
Zone 13b	Continuous Production

Crop Details

Trait	Value
Days to Maturity	50
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	75
Min Soil Temp (°F)	60
Min Night Temp (°F)	50
Harden Off (days)	10

Culinary Notes

Chef's Note

Thai Sweet basil is all about timing: add it late so the leaf stays tender and the sweet-anise aroma doesn’t turn dull. Its clove lift plays especially well with salty fish sauce and bright lime—like a fragrant top note over heat and fat.

Best Uses

torn-leaf garnish for hot bowls (pho, curry, brothy noodles) so the aroma hits before it cools
quick wok or pan-stir sauces—basil goes in late to keep that anise-sweet edge
Thai-style basil stir-fry with salty fat (use sparingly at the end for maximum fragrance)
sweet vinegar quick pickling of basil stems/leaves for punchy, aromatic snacking

Flavor Profile

sweet-anise perfume gentle clove-like lift tender, lush leaf texture aromatic sweetness that stays bright in warm cooking

Kitchen Pairings

fish sauce lime juice garlic chili coconut milk brown sugar

Frequently Asked Questions

What pest or disease commonly affects Ocimum basilicum (Thai sweet basil), and how can I fix it?

Thai sweet basil (Ocimum basilicum var. thyrsiflora) is especially prone to downy mildew and leaf spot in humid weather. Improve airflow by spacing plants well and watering at the soil line (not the leaves), then remove badly infected leaves promptly to slow spread. If conditions stay humid, use an approved downy mildew treatment labeled for basil and follow the label timing before symptoms worsen.

How often should I water Thai sweet basil during peak growth?

During active growth (roughly weeks 2–8), keep the root zone consistently evenly moist, not soggy. Water when the top 1 inch of soil feels dry; in warm Full Sun, this is often about 1–2 times per week depending on your soil and container size. Aim for thorough soaking each time so moisture reaches the basil’s shallow roots, and avoid frequent light sprinkles that leave the soil surface wet but the roots dry.

How do I know when Thai sweet basil is ready to harvest?

Harvest when plants are about 8–12 inches tall and before flowering starts—around 45–50 days from sowing for best flavor and tenderness. Pinch or cut above a leaf pair to encourage branching, and take small harvests early in the morning for the most aromatic leaves. Once flower buds form, leaf quality drops, so harvest regularly until you see flowering clearly.