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When to Plant Broccoli in Grand County, UT

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.

Grand County, Utah is in USDA Zone 6a. The average last spring frost is April 19 and the first fall frost is October 13, giving you a growing season of approximately 177 days.

At an elevation of 5,415 feet, Grand County receives approximately 23.1 inches of rainfall annually with predominantly loam soil. Summer highs average 91ยฐF, providing good warmth for Broccoli during the growing season.

Grand County, UT (Zone 6a) Moderate season
177 days
Last Spring Frost April 19
177 growing days
First Fall Frost October 13

Grand County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (70 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jun 15 – Jul 27
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 2
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jul 9 – Aug 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
0.6″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,421 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Broccoli needs ~1,369 GDD — county provides 3,230 GDD Excellent fit

Broccoli Planting Timeline โ€” Grand County, UT

Broccoli Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors April 19 Apr 19 โ€“ May 3
Direct Sow April 5 Apr 5 โ€“ Apr 26
Fall Sowing August 4 Aug 4 โ€“ Aug 18
Harvest June 21 Jun 21 โ€“ Aug 2

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors
June Harvest
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

177 days

Growing Tips for Grand 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 Grand County, UT?

Grand County is in Zone 6a with an average last frost of April 19. Plan your Broccoli planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grand County, UT?

Grand County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is April 19 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

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