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When to plant Thai Basil in Chartley, MA

For Thai Basil in Chartley, the safe spring window opens around May 3 and closes around May 24. Last expected frost is April 26, first fall frost October 17, giving a 174-day growing season.

When to Plant Thai Basil in Chartley, MA

Bristol County, Massachusetts Zone 7a June

Your June gardening checklist

Here's what deserves your attention in Bristol County, Massachusetts this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost April 26
Avg. first frost October 17
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 15 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.

Chartley, Massachusetts is in USDA Zone 7a. The average last spring frost is April 26 and the first fall frost is October 17, giving you a growing season of approximately 174 days.

At an elevation of 833 feet, Bristol County receives approximately 47.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Thai Basil during the growing season.

Chartley, MA (Zone 7a) Moderate season
174 days
Last Spring Frost April 26
174 growing days
First Fall Frost October 17

Chartley Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Thai Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Mar 1 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 30
Recommended (50%) ✓ Fits season (41 days to spare)
Start indoors: Mar 8 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Mar 26 Transplant: May 28 🍅 Harvest: Jul 23 – Sep 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 Chartley

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

Soil pH

Your soil pH (5.1–6.7) is more acidic than Thai Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.7%). 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

4
successive plantings in your 174-day season

Sow every 5.7 weeks. Last sowing by Aug 03 to harvest before frost.

Thai Basil 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 3.8" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.3" 4.4" 0" ✅ Rainfall sufficient
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.2" 0.1" 💧 Light watering
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 3.7" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Bristol 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 ~1,047 GDD — county provides 2,914 GDD Excellent fit

Thai Basil Planting Timeline — Chartley, MA

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Harvest July 5 Jul 5 – Sep 6

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7a

📆 Growing Season

174 days in Bristol County

Growing Tips for Thai Basil in Chartley

Direct sow Thai Basil outdoors after April 26 in Bristol 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 →

When should I plant Thai Basil in Chartley, MA?

In Chartley, MA, plant Thai Basil after the last frost (around April 26) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Chartley, MA for Thai Basil?

Chartley sits in USDA Zone 7a. Thai Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Thai Basil grow in Chartley's climate?

Yes — Thai Basil grows well in Chartley's temperate climate. Chartley averages a 174-day frost-free season, with last frost around April 26 and first frost around October 17.

🌱

Your Bristol County Garden Planner — Free

A 22-page printable planner built for Bristol County (Zone 7a). 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 Bristol County, MA. Local conditions may vary. Last updated: June 2026.