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When to Plant Thai Basil in Grayson County, TX

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.

Grayson County, Texas is in USDA Zone 7b. The average last spring frost is March 14 and the first fall frost is November 18, giving you a growing season of approximately 249 days.

At an elevation of 248 feet, Grayson County receives approximately 71.2 inches of rainfall annually with predominantly loam soil. Summer highs average 88ยฐF, providing good warmth for Thai Basil during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Thai Basil root diseases.

Grayson County, TX (Zone 7b) Long season
249 days
Last Spring Frost March 14
249 growing days
First Fall Frost November 18

Grayson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (116 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 15 – Jul 17
Recommended (50%) ✓ Fits season (116 days to spare)
Start indoors: Jan 24 Transplant: Mar 28 🍅 Harvest: May 23 – Jul 25
Safe Start (90%) ✓ Fits season (99 days to spare)
Start indoors: Feb 23 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 24

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 Grayson County

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

Soil pH

Your soil pH (6.6โ€“7.3) overlaps with Thai Basil's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). 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 249-day season

Sow every 5.7 weeks. Last sowing by Sep 04 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 โ€” 1.9" 0" โ„๏ธ Dormant
Feb โ€” 2.2" 0" โ„๏ธ Dormant
Mar 4.3" 3.9" 0.4" ๐Ÿ’ง Light watering
Apr 4.3" 8.5" 0" โœ… Rainfall sufficient
May 4.3" 11.3" 0" โœ… Rainfall sufficient
Jun 4.3" 12.4" 0" โœ… Rainfall sufficient
Jul 4.3" 9.3" 0" โœ… Rainfall sufficient
Aug 4.3" 7.7" 0" โœ… Rainfall sufficient
Sep 4.3" 6.2" 0" โœ… Rainfall sufficient
Oct 4.3" 4.1" 0.2" ๐Ÿ’ง Light watering
Nov 4.3" 2.1" 2.2" ๐Ÿšฟ Regular watering
Dec โ€” 1.6" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Grayson County). Supplement amounts are based on average rainfall โ€” 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" 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.

Thai Basil needs ~1,000 GDD — county provides 3,984 GDD Excellent fit

Thai Basil Planting Timeline โ€” Grayson County, TX

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors January 24 Jan 24 โ€“ Feb 7
Transplant Outdoors March 28 Mar 28 โ€“ Apr 11
Direct Sow March 21 Mar 21 โ€“ Apr 11
Harvest May 23 May 23 โ€“ Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/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 7b

๐Ÿ“† Growing Season

249 days in Grayson County

Growing Tips for Thai Basil in Grayson County

Direct sow Thai Basil outdoors after March 14 in Grayson 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 Grayson County, TX?

Grayson County is in Zone 7b with an average last frost of March 14. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grayson County, TX?

Grayson County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 14 and first fall frost is November 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grayson County gardeners in Zone 7b 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 Grayson County, TX. Local conditions may vary. Last updated: April 2026.