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When to Plant Broccoli in Kalamazoo County, MI

Broccoli is a nutrient-dense cool-season crop that produces large central heads followed by smaller side shoots. It is one of the most popular garden vegetables.

Kalamazoo County, Michigan is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 14, giving you a growing season of approximately 165 days.

At an elevation of 1,395 feet, Kalamazoo County receives approximately 32.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Broccoli during the growing season.

Kalamazoo County, MI (Zone 6a) Moderate season
165 days
Last Spring Frost May 2
165 growing days
First Fall Frost October 14

Kalamazoo County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (59 days to spare)
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 10
Recommended (50%) ✓ Fits season (60 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 15
Safe Start (90%) ✓ Fits season (53 days to spare)
Start indoors: Apr 16 Transplant: May 21 🍅 Harvest: Jul 23 – Sep 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 265 gal / 100 sq ft
Broccoli needs ~1,031 GDD — county provides 2,268 GDD Excellent fit

Broccoli Planting Timeline โ€” Kalamazoo County, MI

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing August 5 Aug 5 โ€“ Aug 19
Harvest July 4 Jul 4 โ€“ Aug 15

Plant 1" deep ยท 15" apart ยท Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

165 days

Growing Tips for Kalamazoo County

Start seeds indoors 6-8 weeks before last frost. Provide consistent moisture to prevent hollow stems. Harvest heads before yellow flowers appear.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

๐ŸŒพ Save Your Own Broccoli Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Allow plants to flower 2nd year; collect dry pods.
Storage Store airtight; viable 5 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from other brassicas. Biennial โ€” must overwinter roots.

Frequently Asked Questions

When should I plant Broccoli in Kalamazoo County, MI?

Kalamazoo County is in Zone 6a with an average last frost of May 2. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kalamazoo County, MI?

Kalamazoo County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 2 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kalamazoo County gardeners in Zone 6a 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 Kalamazoo County, MI. Local conditions may vary. Last updated: April 2026.