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When to Plant Thai Basil in Sept-Iles, QC

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.

Sept-Iles, Quebec is in USDA Zone 4a. The average last spring frost is May 16 and the first fall frost is October 3, giving you a growing season of approximately 140 days.

At an elevation of 173 feet, Sept-Iles receives approximately 19.5 inches of rainfall annually with predominantly gray-brown podzol soil. Summer highs average 70°F, so choose short-season varieties of Thai Basil to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Thai Basil successfully. Mulch heavily to conserve soil moisture.

Sept-Iles, QC (Zone 4a) Short season
140 days
Last Spring Frost May 16
140 growing days
First Fall Frost October 3

Sept-Iles Soil Profile

Soil Type

Gray-Brown Podzol

Soil pH

6.0-7.0

Drainage

Well Drained

Thai Basil Planting Timeline — Sept-Iles, QC

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors June 6 Jun 6 – Jun 20
Direct Sow May 23 May 23 – Jun 13
Harvest August 1 Aug 1 – Oct 3

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4a

📆 Growing Season

140 days in Sept-Iles

Growing Tips for Sept-Iles

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 Sept-Iles, QC?

Sept-Iles is in Zone 4a with an average last frost of May 16. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sept-Iles, QC?

Sept-Iles, Quebec is in USDA Hardiness Zone 4a. The average last spring frost is May 16 and first fall frost is October 3.

🌱

Your Sept-Iles Garden Planner — Free

A 22-page printable planner built for Sept-Iles (Zone 4a). 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 Sept-Iles, QC. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.