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When to Plant Thai Basil in Morgan 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.

Morgan County, Tennessee is in USDA Zone 7a. The average last spring frost is April 9 and the first fall frost is October 28, giving you a growing season of approximately 202 days.

At an elevation of 1,116 feet, Morgan County receives approximately 41.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Thai Basil during the growing season.

Morgan County, TN (Zone 7a) Long season
202 days
Last Spring Frost April 9
202 growing days
First Fall Frost October 28

Morgan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (67 days to spare)
Start indoors: Feb 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Aug 14
Recommended (50%) ✓ Fits season (69 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 20
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Mar 11 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 9

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.

Soil Compatibility in Morgan County

How your county's soil matches Thai Basil's growing requirements.

Soil pH

Your soil pH (5.3โ€“7.0) overlaps with Thai Basil's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Morgan County is excellent for Thai Basil โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Thai Basil.

How to Plant Thai Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Thai Basil

4
successive plantings in your 202-day season

Sow every 5.7 weeks. Last sowing by Aug 14 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 309 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Thai Basil

Thai Basil needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Thai Basil Needs Rainfall You Supplement Action
Jan โ€” 3.1" 0" โ„๏ธ Dormant
Feb โ€” 2.8" 0" โ„๏ธ Dormant
Mar โ€” 3.8" 0" โ„๏ธ Dormant
Apr 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
May 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Jun 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Jul 4.3" 4.4" 0" โœ… Rainfall sufficient
Aug 4.3" 4.3" 0" โœ… Rainfall sufficient
Sep 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Oct 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Nov โ€” 3.5" 0" โ„๏ธ Dormant
Dec โ€” 2.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Morgan County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Thai Basil Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Thai Basil needs ~1,094 GDD — county provides 3,535 GDD Excellent fit

Thai Basil Planting Timeline โ€” Morgan County, TN

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors February 19 Feb 19 โ€“ Mar 5
Transplant Outdoors April 23 Apr 23 โ€“ May 7
Direct Sow April 16 Apr 16 โ€“ May 7
Harvest June 18 Jun 18 โ€“ Aug 20

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7a

๐Ÿ“† Growing Season

202 days in Morgan County

Growing Tips for Thai Basil in Morgan County

Direct sow Thai Basil outdoors after April 09 in Morgan County when soil has warmed and frost danger has passed.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Morgan County is in Zone 7a with an average last frost of April 9. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morgan County, TN?

Morgan County, Tennessee is in USDA Hardiness Zone 7a. The average last spring frost is April 9 and first fall frost is October 28.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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