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When to Plant Broccoli in Golden Valley County, MT

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.

Golden Valley County, Montana is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 20, giving you a growing season of approximately 121 days.

At an elevation of 7,917 feet, Golden Valley County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Broccoli to ensure they mature before fall.

Golden Valley County, MT (Zone 4a) Short season
121 days
Last Spring Frost May 22
121 growing days
First Fall Frost September 20

Golden Valley County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (12 days to spare)
Start indoors: Apr 6 Transplant: May 18 🍅 Harvest: Jul 20 – Aug 31
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Jul 24 – Sep 4
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 26 Transplant: Jun 7 🍅 Harvest: Aug 9 – Sep 20

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
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 171 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Broccoli needs ~919 GDD — county provides 1,482 GDD Excellent fit

Broccoli Planting Timeline โ€” Golden Valley County, MT

Broccoli Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors May 22 May 22 โ€“ Jun 5
Direct Sow May 15 May 15 โ€“ Jun 5
Fall Sowing June 28 Jun 28 โ€“ Jul 12
Harvest July 24 Jul 24 โ€“ Sep 4

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 Fall Sowing
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 4a

Growing Season

121 days

Growing Tips for Golden Valley 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 Golden Valley County, MT?

Golden Valley County is in Zone 4a with an average last frost of May 22. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Golden Valley County, MT?

Golden Valley County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Golden Valley County gardeners in Zone 4a 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 Golden Valley County, MT. Local conditions may vary. Last updated: April 2026.