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When to plant Thai Basil in Nassau County, FL

In Nassau County, plant Thai Basil in spring between February 21 and March 14, once soil temps hold above 50°F. Nassau County's last frost averages February 14, so aim for a steady week of warm soil before planting. For a fall crop, sow between and — roughly 50–75 days before the first frost on December 1.

When to Plant Thai Basil in Nassau County, FL

Nassau County, Florida Zone 9a June

What to do in June

Welcome to June in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 14
Avg. first frost December 1
Soil temp (4") 85°F
Watering Low
Pest pressure High
Daylight 14 hrs

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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.

Nassau County, Florida is in USDA Zone 9a. The average last spring frost is February 14 and the first fall frost is December 1, giving you a growing season of approximately 290 days.

At an elevation of 408 feet, Nassau County receives approximately 57.9 inches of rainfall annually with predominantly sand soil. Summer highs average 101°F, so Thai Basil may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Thai Basil will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Thai Basil root diseases.

Nassau County, FL (Zone 9a) Year-round
290 days
Last Spring Frost February 14
290 growing days
First Fall Frost December 1

Nassau County Soil Profile

Soil Type

Sand

Soil pH

5.2-5.8

Drainage

Well Drained

Thai Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (162 days to spare)
Start indoors: Dec 27 Transplant: Feb 14 🍅 Harvest: Apr 11 – Jun 13
Recommended (50%) ✓ Fits season (164 days to spare)
Start indoors: Jan 3 Transplant: Feb 21 🍅 Harvest: Apr 18 – Jun 20
Safe Start (90%) ✓ Fits season (146 days to spare)
Start indoors: Feb 9 Transplant: Mar 30 🍅 Harvest: May 25 – Jul 27

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 Nassau County

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

Soil pH

Your soil pH (5.2–5.8) is more acidic than Thai Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Nassau County warms quickly in spring but drains fast. Thai Basil will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.4%). Add 2-3 inches of compost before planting Thai Basil.

How to Plant Thai Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Thai Basil

7
successive plantings in your 290-day season

Sow every 5.7 weeks. Last sowing by Sep 17 to harvest before frost.

Thai Basil Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 426 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 2.8" 0" ❄️ Dormant
Feb 4.3" 3.2" 1.1" 💧 Light watering
Mar 4.3" 3.7" 0.6" 💧 Light watering
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 6.6" 0" ✅ Rainfall sufficient
Jul 4.3" 7.9" 0" ✅ Rainfall sufficient
Aug 4.3" 8.7" 0" ✅ Rainfall sufficient
Sep 4.3" 7.9" 0" ✅ Rainfall sufficient
Oct 4.3" 5.3" 0" ✅ Rainfall sufficient
Nov 4.3" 2.2" 2.1" 💧 Light watering
Dec 4.3" 2.5" 1.8" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Nassau 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 ~1,609 GDD — county provides 7,493 GDD Excellent fit

Thai Basil Planting Timeline — Nassau County, FL

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors January 3 Jan 3 – Jan 17
Transplant Outdoors February 21 Feb 21 – Mar 7
Direct Sow February 21 Feb 21 – Mar 14
Harvest April 18 Apr 18 – Jun 20

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

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Transplant Outdoors Direct Sow
April Harvest
May Harvest
June Harvest
July
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: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

290 days in Nassau County

Growing Tips for Thai Basil in Nassau County

Direct sow Thai Basil outdoors after February 14 in Nassau County when soil has warmed and frost danger has passed.

Sandy soil in Nassau County dries quickly — mulch Thai Basil with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 101°F in Nassau County, provide afternoon shade for Thai Basil and water deeply in the morning.

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 Nassau County, FL?

Nassau County is in Zone 9a with an average last frost of February 14. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Nassau County, FL?

Nassau County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is February 14 and first fall frost is December 1.

When should I plant Thai Basil in Nassau County, FL?

In Nassau County, FL, plant Thai Basil after the last frost (around February 14) and before the first frost (around December 1). Best results when soil holds above 50°F.

What growing zone is Nassau County, FL for Thai Basil?

Nassau County sits in USDA Zone 9a. Thai Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Thai Basil grow in Nassau County's climate?

Yes — Thai Basil grows well in Nassau County's temperate climate. Nassau County averages a 291-day frost-free season, with last frost around February 14 and first frost around December 1.

🌱

Your Nassau County Garden Planner — Free

A 22-page printable planner built for Nassau 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 Nassau County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

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