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When to Plant Comfrey in Haut-Richelieu, QC

Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Haut-Richelieu, Quebec is in USDA Zone 6a. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 131 feet, Haut-Richelieu receives approximately 36.9 inches of rainfall annually with predominantly gray-brown podzol soil. Summer highs average 78°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Haut-Richelieu, QC (Zone 6a) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Haut-Richelieu 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 (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Sep 2
Recommended (50%) ✓ Fits season (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Sep 2
Safe Start (90%) ✓ Fits season (43 days to spare)
Transplant: Apr 22 🍅 Harvest: Jun 24 – Sep 2

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 Comfrey

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 223 gal / 100 sq ft

Monthly Watering Guide for Comfrey

Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Comfrey Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.4" 0" ✅ Rainfall sufficient
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Haut-Richelieu). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Comfrey 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.

Comfrey needs ~638 GDD — county provides 1,530 GDD Excellent fit

Comfrey Planting Timeline — Haut-Richelieu, QC

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors April 27 Apr 27 – May 11
Harvest June 29 Jun 29 – Sep 7

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

180 days in Haut-Richelieu

Growing Tips for Haut-Richelieu

Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Comfrey in Haut-Richelieu, QC?

Haut-Richelieu is in Zone 6a with an average last frost of April 20. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haut-Richelieu, QC?

Haut-Richelieu, Quebec is in USDA Hardiness Zone 6a. The average last spring frost is April 20 and first fall frost is October 17.

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Your Haut-Richelieu Garden Planner — Free

A 24-page printable planner built for Haut-Richelieu (Zone 6a). 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 Haut-Richelieu, QC. Local conditions may vary. Last updated: April 2026.

Sources & credits

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