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When to Plant Broccoli in Montmorency 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.

Montmorency County, Michigan is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is October 1, giving you a growing season of approximately 135 days.

At an elevation of 1,107 feet, Montmorency County receives approximately 40.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Broccoli to ensure they mature before fall.

Montmorency County, MI (Zone 4b) Short season
135 days
Last Spring Frost May 19
135 growing days
First Fall Frost October 1

Montmorency County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Jul 17 – Aug 28
Recommended (50%) ✓ Fits season (30 days to spare)
Start indoors: Apr 7 Transplant: May 19 🍅 Harvest: Jul 21 – Sep 1
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 15

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
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Broccoli needs ~919 GDD — county provides 1,653 GDD Excellent fit

Broccoli Planting Timeline โ€” Montmorency County, MI

Broccoli Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 โ€“ Apr 21
Transplant Outdoors May 19 May 19 โ€“ Jun 2
Direct Sow May 12 May 12 โ€“ Jun 2
Fall Sowing July 9 Jul 9 โ€“ Jul 23
Harvest July 21 Jul 21 โ€“ Sep 1

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing Harvest
August Harvest
September Harvest
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 4b

Growing Season

135 days

Growing Tips for Montmorency 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 Montmorency County, MI?

Montmorency County is in Zone 4b with an average last frost of May 19. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Montmorency County, MI?

Montmorency County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is October 1.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Montmorency County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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 Montmorency County, MI. Local conditions may vary. Last updated: April 2026.