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When to Plant Thai Basil in Sagadahoc County, ME

Sagadahoc County, Maine Zone 5b May

May in Sagadahoc County, Maine — your action list

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 29
Avg. first frost October 13
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Plant out thai basil

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Seed thai basil outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

Looking ahead to June
  • Starting indoors: 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.

Sagadahoc County, Maine is in USDA Zone 5b. The average last spring frost is April 29 and the first fall frost is October 13, giving you a growing season of approximately 167 days.

At an elevation of 1,163 feet, Sagadahoc County receives approximately 43.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Thai Basil during the growing season.

Sagadahoc County, ME (Zone 5b) Moderate season
167 days
Last Spring Frost April 29
167 growing days
First Fall Frost October 13
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Sagadahoc County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Mar 5 Transplant: May 7 🍅 Harvest: Jul 2 – Sep 3
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Mar 11 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 9
Safe Start (90%) ✓ Fits season (38 days to spare)
Start indoors: Mar 23 Transplant: May 25 🍅 Harvest: Jul 20 – Sep 21

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 Sagadahoc County

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

Soil pH

Your soil pH (4.9–6.3) is more acidic than Thai Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). 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

3
successive plantings in your 167-day season

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/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 2.8" 0" ❄️ Dormant
Feb 3.2" 0" ❄️ Dormant
Mar 4" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.2" 0.1" 💧 Light watering
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.3" 1" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Sagadahoc 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 ~953 GDD — county provides 2,546 GDD Excellent fit

Thai Basil Planting Timeline — Sagadahoc County, ME

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 8 Jul 8 – Sep 9

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
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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 5b

📆 Growing Season

167 days in Sagadahoc County

Growing Tips for Thai Basil in Sagadahoc County

Direct sow Thai Basil outdoors after April 29 in Sagadahoc 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 Sagadahoc County, ME?

Sagadahoc County is in Zone 5b with an average last frost of April 29. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sagadahoc County, ME?

Sagadahoc County, Maine is in USDA Hardiness Zone 5b. The average last spring frost is April 29 and first fall frost is October 13.

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Your Sagadahoc County Garden Planner — Free

A 24-page printable planner built for Sagadahoc County (Zone 5b). 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 Sagadahoc County, ME. 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.