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When to Plant Cauliflower in Morgan County, CO

Cauliflower is a cool-season brassica that produces dense white, purple, or green heads called curds. It is more finicky than broccoli but rewards with a mild, nutty flavor.

Morgan County, Colorado is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 7,673 feet, Morgan County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Cauliflower to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cauliflower successfully. Mulch heavily to conserve soil moisture.

Morgan County, CO (Zone 5a) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Morgan County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jun 27 – Aug 29
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Jul 5 – Sep 6
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Jul 15 – Sep 16

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
1.5″/week
Rainfall provides
0.5″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 1,573 gal / 100 sq ft
Drought risk

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

Cauliflower needs ~1,008 GDD — county provides 1,924 GDD Excellent fit

Cauliflower Planting Timeline โ€” Morgan County, CO

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow April 26 Apr 26 โ€“ May 17
Fall Sowing July 27 Jul 27 โ€“ Aug 10
Harvest July 5 Jul 5 โ€“ Sep 6

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

55โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

148 days

Growing Tips for Morgan County

Start seeds indoors 6 weeks before transplanting. Blanch white varieties by tying outer leaves over the head. Provide consistent moisture and avoid temperature extremes.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Strawberries

Level Up Your Garden

Frequently Asked Questions

When should I plant Cauliflower in Morgan County, CO?

Morgan County is in Zone 5a with an average last frost of May 10. Plan your Cauliflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morgan County, CO?

Morgan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Morgan County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Morgan County, CO. Local conditions may vary. Last updated: April 2026.