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When to Plant Thai Basil in Jefferson County, MS

Jefferson County, Mississippi Zone 8b May

Your May planting checklist for Jefferson County, Mississippi

Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 12
Avg. first frost November 13
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Bring in the thai basil

    If you can't use it all right away, check the food-preservation section of your planner.

To set up a strong June, finish these tasks
  • 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.

Jefferson County, Mississippi is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 13, giving you a growing season of approximately 246 days.

At an elevation of 82 feet, Jefferson County receives approximately 55.9 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°F, providing good warmth for Thai Basil during the growing season. Clay soil retains moisture well for Thai Basil, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Thai Basil root diseases.

Jefferson County, MS (Zone 8b) Long season
246 days
Last Spring Frost March 12
246 growing days
First Fall Frost November 13

Jefferson County Soil Profile

Soil Type

Clay Loam

Soil pH

5.8-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (109 days to spare)
Start indoors: Jan 16 Transplant: Mar 20 🍅 Harvest: May 15 – Jul 17
Recommended (50%) ✓ Fits season (113 days to spare)
Start indoors: Jan 22 Transplant: Mar 26 🍅 Harvest: May 21 – Jul 23
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Jun 17 – Aug 19

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 Jefferson County

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

Soil pH

Your soil pH (5.8–6.5) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

The clay loam soil in Jefferson 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 (2.8%). 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 246-day season

Sow every 5.7 weeks. Last sowing by Aug 30 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 5.1" 0" ❄️ Dormant
Feb 4.4" 0" ❄️ Dormant
Mar 4.3" 5.9" 0" ✅ Rainfall sufficient
Apr 4.3" 4.6" 0" ✅ Rainfall sufficient
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.2" 0" ✅ Rainfall sufficient
Jul 4.3" 6.1" 0" ✅ Rainfall sufficient
Aug 4.3" 4.8" 0" ✅ Rainfall sufficient
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 4.5" 0" ✅ Rainfall sufficient
Dec 4.1" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Jefferson 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 ~1,281 GDD — county provides 5,043 GDD Excellent fit

Thai Basil Planting Timeline — Jefferson County, MS

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors January 22 Jan 22 – Feb 5
Transplant Outdoors March 26 Mar 26 – Apr 9
Direct Sow March 19 Mar 19 – Apr 9
Harvest May 21 May 21 – Jul 23

Plant 0.5" deep · 8" apart · 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
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

246 days in Jefferson County

Growing Tips for Thai Basil in Jefferson County

Direct sow Thai Basil outdoors after March 12 in Jefferson County when soil has warmed and frost danger has passed.

With Jefferson County's clay soil (30% clay), work in 3-4 inches of compost before planting Thai Basil. Avoid tilling when soil is wet to prevent compaction.

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 Jefferson County, MS?

Jefferson County is in Zone 8b with an average last frost of March 12. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, MS?

Jefferson County, Mississippi is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 13.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 8b). 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 Jefferson County, MS. 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.