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When to Plant Radish in Haut-Richelieu, QC

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

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 Radish 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 (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3
Recommended (50%) ✓ Fits season (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3
Safe Start (90%) ✓ Fits season (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3

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 Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Radish

Radish needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Radish Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 3.6" 0" ✅ Rainfall sufficient
May 2.2" 4.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.4" 0" ✅ Rainfall sufficient
Jul 2.2" 4.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.9" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
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.

Radish 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.

Radish needs ~242 GDD — county provides 1,530 GDD Excellent fit

Radish Planting Timeline — Haut-Richelieu, QC

Radish Planting Calendar

Activity When Date Range
Direct Sow April 6 Apr 6 – Apr 27
Harvest May 4 May 4 – May 25
Fall Sowing August 8 Aug 8 – Aug 22

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May Harvest
June
July
August Fall Sowing
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

180 days in Haut-Richelieu

Growing Tips for Radish in Haut-Richelieu

Your generous 180.0-day season in Haut-Richelieu allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.

Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

Haut-Richelieu is in Zone 6a with an average last frost of April 20. Plan your Radish 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.

🌱

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

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