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When to Plant Cumin in Grey-Bruce, ON

Cumin is a warm-season annual herb whose seeds are one of the most widely used spices globally. It requires a long, hot growing season of 3-4 months.

Grey-Bruce, Ontario 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 984 feet, Grey-Bruce receives approximately 39 inches of rainfall annually with predominantly clay loam soil. Summer highs average 83°F, so choose short-season varieties of Cumin to ensure they mature before fall. Clay soil retains moisture well for Cumin, but amend with compost to improve drainage and prevent root rot.

Grey-Bruce, ON (Zone 6a) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17
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Grey-Bruce Soil Profile

Soil Type

Clay Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: Jul 22 – Sep 23
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: Jul 22 – Sep 23
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Mar 11 Transplant: Apr 8 🍅 Harvest: Jul 22 – Sep 23

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 Cumin

0.5"
Planting Depth
8"
Between Plants
12"
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 Cumin

Cumin 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 Cumin Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.2" 3.4" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 5.1" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.8" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Cumin 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.

Cumin needs ~1,348 GDD — county provides 2,205 GDD Excellent fit

Cumin Planting Timeline — Grey-Bruce, ON

Cumin Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow April 6 Apr 6 – Apr 27
Harvest July 27 Jul 27 – Sep 28
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–8 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

180 days in Grey-Bruce

Growing Tips for Cumin in Grey-Bruce

Common pests for Cumin in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 4 weeks before last frost. Transplant after all danger of frost. Harvest when seed heads turn brown. Requires consistent warmth for proper seed development.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cumin in Grey-Bruce, ON?

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

What planting zone is Grey-Bruce, ON?

Grey-Bruce, Ontario 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 Grey-Bruce Garden Planner — Free

A 24-page printable planner built for Grey-Bruce (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grey-Bruce, ON. 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.