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When to Plant Thai Basil in St. Francis County, AR

St. Francis County, Arkansas Zone 8a May

What to do in May

Here's what deserves your attention in St. Francis County, Arkansas this month. Everything below is tailored to Zone 8a and timed around your local frost dates.

Avg. last frost March 20
Avg. first frost November 9
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Begin indoor sowing: thai basil

    You're about 27 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Collect thai basil at their peak

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

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.

St. Francis County, Arkansas is in USDA Zone 8a. The average last spring frost is March 20 and the first fall frost is November 9, giving you a growing season of approximately 234 days.

At an elevation of 1,429 feet, St. Francis County receives approximately 51.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°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.

St. Francis County, AR (Zone 8a) Long season
234 days
Last Spring Frost March 20
234 growing days
First Fall Frost November 9

St. Francis County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (101 days to spare)
Start indoors: Jan 22 Transplant: Mar 26 🍅 Harvest: May 21 – Jul 23
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Jan 30 Transplant: Apr 3 🍅 Harvest: May 29 – Jul 31
Safe Start (90%) ✓ Fits season (100 days to spare)
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Jun 18 – Aug 20

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 St. Francis County

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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 234-day season

Sow every 5.7 weeks. Last sowing by Aug 26 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 169 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 4.2" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 4.3" 5.4" 0" ✅ Rainfall sufficient
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 5.2" 0" ✅ Rainfall sufficient
Aug 4.3" 4.5" 0" ✅ Rainfall sufficient
Sep 4.3" 4.1" 0.2" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 4.3" 4" 0.3" 💧 Light watering
Dec 4.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in St. Francis 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 ~1,000 GDD — county provides 3,744 GDD Excellent fit

Thai Basil Planting Timeline — St. Francis County, AR

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 – Feb 13
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow March 27 Mar 27 – Apr 17
Harvest May 29 May 29 – Jul 31

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

234 days in St. Francis County

Growing Tips for Thai Basil in St. Francis County

Direct sow Thai Basil outdoors after March 20 in St. Francis 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 St. Francis County, AR?

St. Francis County is in Zone 8a with an average last frost of March 20. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Francis County, AR?

St. Francis County, Arkansas is in USDA Hardiness Zone 8a. The average last spring frost is March 20 and first fall frost is November 9.

🌱

Your St. Francis County Garden Planner — Free

A 24-page printable planner built for St. Francis County (Zone 8a). 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 St. Francis County, AR. 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.