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When to Plant Thai Basil in Greene County, PA

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.

Greene County, Pennsylvania is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.

At an elevation of 603 feet, Greene County receives approximately 48.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Thai Basil during the growing season.

Greene County, PA (Zone 6a) Moderate season
180 days
Last Spring Frost April 23
180 growing days
First Fall Frost October 20

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (53 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (47 days to spare)
Start indoors: Mar 5 Transplant: May 7 🍅 Harvest: Jul 2 – Sep 3
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Mar 25 Transplant: May 27 🍅 Harvest: Jul 22 – Sep 23

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Thai Basil needs ~1,000 GDD — county provides 2,880 GDD Excellent fit

Thai Basil Planting Timeline โ€” Greene County, PA

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 โ€“ Mar 19
Transplant Outdoors May 7 May 7 โ€“ May 21
Direct Sow April 30 Apr 30 โ€“ May 21
Harvest July 2 Jul 2 โ€“ Sep 3

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

Month-by-Month Timeline

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

180 days

Growing Tips for Greene 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 Greene County, PA?

Greene County is in Zone 6a with an average last frost of April 23. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Greene County, PA?

Greene County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Greene 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 Greene County, PA. Local conditions may vary. Last updated: April 2026.