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When to Plant Thai Basil in Pope County, IL

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.

Pope County, Illinois is in USDA Zone 6b. The average last spring frost is April 7 and the first fall frost is October 21, giving you a growing season of approximately 197 days.

At an elevation of 1,120 feet, Pope County receives approximately 39.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91ยฐF, providing good warmth for Thai Basil during the growing season.

Pope County, IL (Zone 6b) Moderate season
197 days
Last Spring Frost April 7
197 growing days
First Fall Frost October 21

Pope County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Start indoors: Feb 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Aug 14
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 16 – Aug 18
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Mar 3 Transplant: May 5 🍅 Harvest: Jun 30 – Sep 1

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
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 814 gal / 100 sq ft
Thai Basil needs ~1,141 GDD — county provides 3,595 GDD Excellent fit

Thai Basil Planting Timeline โ€” Pope County, IL

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 โ€“ Mar 3
Transplant Outdoors April 21 Apr 21 โ€“ May 5
Direct Sow April 14 Apr 14 โ€“ May 5
Harvest June 16 Jun 16 โ€“ Aug 18

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

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 6b

Growing Season

197 days

Growing Tips for Pope 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 Pope County, IL?

Pope County is in Zone 6b with an average last frost of April 7. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Pope County, IL?

Pope County, Illinois is in USDA Hardiness Zone 6b. The average last spring frost is April 7 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

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