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When to Plant Thai Basil in Carlisle County, KY

Carlisle County, Kentucky Zone 7a May

This month in Carlisle County, Kentucky

Your Carlisle County, Kentucky garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 28
Avg. first frost October 31
Soil temp (4") 54°F
Watering Moderate
Pest pressure Low
Daylight 14 hrs
  1. Time to start thai basil inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

A few tasks this May that'll pay off in June
  • First harvests: thai basil

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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.

Carlisle County, Kentucky is in USDA Zone 7a. The average last spring frost is March 28 and the first fall frost is October 31, giving you a growing season of approximately 217 days.

At an elevation of 4,000 feet, Carlisle County receives approximately 44.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Thai Basil during the growing season.

Carlisle County, KY (Zone 7a) Long season
217 days
Last Spring Frost March 28
217 growing days
First Fall Frost October 31

Carlisle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Jan 29 Transplant: Apr 2 🍅 Harvest: May 28 – Jul 30
Recommended (50%) ✓ Fits season (84 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jun 6 – Aug 8
Safe Start (90%) ✓ Fits season (78 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26

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 Carlisle County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Carlisle County is excellent for Thai Basil — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). 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

5
successive plantings in your 217-day season

Sow every 5.7 weeks. Last sowing by Aug 17 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 264 gal / 100 sq ft

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 4" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.3" 4.1" 0.2" 💧 Light watering
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 3.7" 0.6" 💧 Light watering
Jun 4.3" 3.6" 0.7" 💧 Light watering
Jul 4.3" 4.8" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Oct in Carlisle County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 3,797 GDD Excellent fit

Thai Basil Planting Timeline — Carlisle County, KY

Thai Basil Planting Calendar

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

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

217 days in Carlisle County

Growing Tips for Thai Basil in Carlisle County

Direct sow Thai Basil outdoors after March 28 in Carlisle 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 Carlisle County, KY?

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

What planting zone is Carlisle County, KY?

Carlisle County, Kentucky is in USDA Hardiness Zone 7a. The average last spring frost is March 28 and first fall frost is October 31.

🌱

Your Carlisle County Garden Planner — Free

A 24-page printable planner built for Carlisle County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Carlisle County, KY. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.