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When to Plant Thai Basil in Atascosa County, TX

Atascosa County, Texas Zone 9a May

What to do in May

Here's what deserves your attention in Atascosa County, Texas this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost February 26
Avg. first frost November 29
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 13.4 hrs
  1. Collect thai basil at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

A few tasks this May that'll pay off in June
  • First harvests: thai basil

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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.

Atascosa County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 276 days.

At an elevation of 1,942 feet, Atascosa County receives approximately 51.7 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, 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.

Atascosa County, TX (Zone 9a) Year-round
276 days
Last Spring Frost February 26
276 growing days
First Fall Frost November 29

Atascosa County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Jan 2 Transplant: Feb 20 🍅 Harvest: Apr 17 – Jun 19
Recommended (50%) ✓ Fits season (150 days to spare)
Start indoors: Jan 15 Transplant: Mar 5 🍅 Harvest: Apr 30 – Jul 2
Safe Start (90%) ✓ Fits season (143 days to spare)
Start indoors: Feb 8 Transplant: Mar 29 🍅 Harvest: May 24 – Jul 26

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 Atascosa County

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

Soil pH

Your soil pH (6.8–7.7) is more alkaline than Thai Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Atascosa County is excellent for Thai Basil — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Thai Basil.

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

6
successive plantings in your 276-day season

Sow every 5.7 weeks. Last sowing by Sep 15 to harvest before frost.

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 1,272 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 1.5" 0" ❄️ Dormant
Feb 4.3" 1.6" 2.7" 🚿 Regular watering
Mar 4.3" 3.5" 0.8" 💧 Light watering
Apr 4.3" 4.8" 0" ✅ Rainfall sufficient
May 4.3" 7.6" 0" ✅ Rainfall sufficient
Jun 4.3" 7.4" 0" ✅ Rainfall sufficient
Jul 4.3" 7.4" 0" ✅ Rainfall sufficient
Aug 4.3" 6.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4.9" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 2" 2.3" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Feb–Nov in Atascosa County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,141 GDD — county provides 5,055 GDD Excellent fit

Thai Basil Planting Timeline — Atascosa County, TX

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow March 5 Mar 5 – Mar 26
Harvest April 30 Apr 30 – Jul 2

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

276 days in Atascosa County

Growing Tips for Thai Basil in Atascosa County

Direct sow Thai Basil outdoors after February 26 in Atascosa 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 Atascosa County, TX?

Atascosa County is in Zone 9a with an average last frost of February 26. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Atascosa County, TX?

Atascosa County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is November 29.

🌱

Your Atascosa County Garden Planner — Free

A 24-page printable planner built for Atascosa County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Atascosa County, TX. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.