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When to Plant Thai Basil in Hamilton County, TN

Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.

Hamilton County, Tennessee is in USDA Zone 7a. The average last spring frost is March 28 and the first fall frost is November 1, giving you a growing season of approximately 218 days.

At an elevation of 3,918 feet, Hamilton County receives approximately 51.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93ยฐF, providing good warmth for Thai Basil during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Thai Basil root diseases.

Hamilton County, TN (Zone 7a) Long season
218 days
Last Spring Frost March 28
218 growing days
First Fall Frost November 1

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (88 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: May 30 – Aug 1
Recommended (50%) ✓ Fits season (85 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jun 6 – Aug 8
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Feb 27 Transplant: May 1 🍅 Harvest: Jun 26 – Aug 28

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 19 gal / 100 sq ft
Thai Basil needs ~1,234 GDD — county provides 4,305 GDD Excellent fit

Thai Basil Planting Timeline โ€” Hamilton County, TN

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 โ€“ Feb 21
Transplant Outdoors April 11 Apr 11 โ€“ Apr 25
Direct Sow April 4 Apr 4 โ€“ Apr 25
Harvest June 6 Jun 6 โ€“ Aug 8

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March โ€”
April Transplant Outdoors Direct Sow
May โ€”
June Harvest
July Harvest
August Harvest
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“75 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

218 days

Growing Tips for Hamilton County

Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Level Up Your Garden

Frequently Asked Questions

When should I plant Thai Basil in Hamilton County, TN?

Hamilton County is in Zone 7a with an average last frost of March 28. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Hamilton County, TN?

Hamilton County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is March 28 and first fall frost is November 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Hamilton County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Hamilton County, TN. Local conditions may vary. Last updated: April 2026.