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When to Plant Thai Basil in Bathurst, NB

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.

Bathurst, New Brunswick is in USDA Zone 5a. The average last spring frost is May 3 and the first fall frost is October 10, giving you a growing season of approximately 160 days.

At an elevation of 131 feet, Bathurst receives approximately 27.6 inches of rainfall annually with predominantly gray-brown podzol soil. Summer highs average 73ยฐF, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Bathurst, NB (Zone 5a) Moderate season
160 days
Last Spring Frost May 3
160 growing days
First Fall Frost October 10

Bathurst Soil Profile

Soil Type

Gray-Brown Podzol

Soil pH

6.0-7.0

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26
Recommended (50%) ✓ Fits season (50 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jun 24 – Aug 26

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.

How to Plant Thai Basil

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 392 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 โ€” 1.1" 0" โ„๏ธ Dormant
Feb โ€” 1.2" 0" โ„๏ธ Dormant
Mar โ€” 1.7" 0" โ„๏ธ Dormant
Apr โ€” 3" 0" โ„๏ธ Dormant
May 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Jun 4.3" 3.6" 0.7" ๐Ÿ’ง Light watering
Jul 4.3" 2.7" 1.6" ๐Ÿ’ง Light watering
Aug 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Sep 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Oct 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Nov โ€” 2" 0" โ„๏ธ Dormant
Dec โ€” 1.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Bathurst). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~297 GDD — county provides 760 GDD Excellent fit

Thai Basil Planting Timeline โ€” Bathurst, NB

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors May 17 May 17 โ€“ May 31
Direct Sow May 10 May 10 โ€“ May 31
Harvest July 12 Jul 12 โ€“ Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

50โ€“75 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

160 days in Bathurst

Growing Tips for Bathurst

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 Bathurst, NB?

Bathurst is in Zone 5a with an average last frost of May 3. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Bathurst, NB?

Bathurst, New Brunswick is in USDA Hardiness Zone 5a. The average last spring frost is May 3 and first fall frost is October 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Bathurst gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Bathurst, NB. Local conditions may vary. Last updated: April 2026.