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When to Plant Basil in Carroll County, KY

Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Carroll County, Kentucky is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 20, giving you a growing season of approximately 185 days.

At an elevation of 3,005 feet, Carroll County receives approximately 42.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Basil during the growing season.

Carroll County, KY (Zone 6b) Moderate season
185 days
Last Spring Frost April 18
185 growing days
First Fall Frost October 20

Carroll County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (55 days to spare)
Start indoors: Feb 20 Transplant: Apr 24 🍅 Harvest: Jun 19 – Aug 21
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 29
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 20 Transplant: May 22 🍅 Harvest: Jul 17 – Sep 18

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 Carroll County

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

Soil pH

Your soil pH (5.5โ€“7.0) overlaps with Basil's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Basil.

How to Plant Basil

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

Succession Planting Basil

4
successive plantings in your 185-day season

Sow every 5.7 weeks. Last sowing by Aug 06 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan โ€” 3.7" 0" โ„๏ธ Dormant
Feb โ€” 3.6" 0" โ„๏ธ Dormant
Mar โ€” 3.7" 0" โ„๏ธ Dormant
Apr 2.6" 2.8" 0" โœ… Rainfall sufficient
May 2.6" 3.5" 0" โœ… Rainfall sufficient
Jun 2.6" 4.3" 0" โœ… Rainfall sufficient
Jul 2.6" 4.2" 0" โœ… Rainfall sufficient
Aug 2.6" 4.5" 0" โœ… Rainfall sufficient
Sep 2.6" 3" 0" โœ… Rainfall sufficient
Oct 2.6" 3" 0" โœ… Rainfall sufficient
Nov โ€” 2.8" 0" โ„๏ธ Dormant
Dec โ€” 3.3" 0" โ„๏ธ Dormant

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

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.

Basil needs ~1,094 GDD — county provides 3,237 GDD Excellent fit

Basil Planting Timeline โ€” Carroll County, KY

Basil Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 โ€“ Mar 14
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 25 Apr 25 โ€“ May 16
Harvest June 27 Jun 27 โ€“ Aug 29

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 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

0.6"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6b

๐Ÿ“† Growing Season

185 days in Carroll County

Growing Tips for Basil in Carroll County

Direct sow Basil outdoors after April 18 in Carroll County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Carroll County, KY?

Carroll County is in Zone 6b with an average last frost of April 18. Plan your Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Carroll County, KY?

Carroll County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Carroll County gardeners in Zone 6b 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 Carroll County, KY. Local conditions may vary. Last updated: April 2026.