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When to Plant Thai Basil in Lawrence 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.

Lawrence County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 27, giving you a growing season of approximately 197 days.

At an elevation of 969 feet, Lawrence County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Thai Basil during the growing season.

Lawrence County, IL (Zone 6a) Moderate season
197 days
Last Spring Frost April 13
197 growing days
First Fall Frost October 27

Lawrence County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 24
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Mar 9 Transplant: May 11 🍅 Harvest: Jul 6 – Sep 7

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
0.3″/week
Watering frequency Only during dry spells
Season total 521 gal / 100 sq ft
Drought risk

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

Thai Basil needs ~1,000 GDD — county provides 3,152 GDD Excellent fit

Thai Basil Planting Timeline โ€” Lawrence County, IL

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 โ€“ Mar 9
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Direct Sow April 20 Apr 20 โ€“ May 11
Harvest June 22 Jun 22 โ€“ Aug 24

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 6a

Growing Season

197 days

Growing Tips for Lawrence 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 Lawrence County, IL?

Lawrence County is in Zone 6a with an average last frost of April 13. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lawrence County, IL?

Lawrence County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 27.

๐ŸŒฑ

Plan Your Garden with Confidence

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