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When to Plant Cauliflower in Des Moines County, IA

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.

Des Moines County, Iowa is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 16, giving you a growing season of approximately 182 days.

At an elevation of 606 feet, Des Moines County receives approximately 38.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Cauliflower during the growing season.

Des Moines County, IA (Zone 5b) Moderate season
182 days
Last Spring Frost April 17
182 growing days
First Fall Frost October 16

Des Moines County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: Jun 7 – Aug 9
Recommended (50%) ✓ Fits season (63 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jun 12 – Aug 14
Safe Start (90%) ✓ Fits season (62 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Jun 28 – Aug 30

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
0.9″/week
You supply
1.3″/week
Watering frequency 2-3 times/week
Season total 2,050 gal / 100 sq ft
Drought risk

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

Cauliflower needs ~1,066 GDD — county provides 2,502 GDD Excellent fit

Cauliflower Planting Timeline โ€” Des Moines County, IA

Cauliflower Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 โ€“ Mar 27
Transplant Outdoors April 17 Apr 17 โ€“ May 1
Direct Sow April 3 Apr 3 โ€“ Apr 24
Fall Sowing August 7 Aug 7 โ€“ Aug 21
Harvest June 12 Jun 12 โ€“ Aug 14

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

High โ€” keep soil consistently moist

Days to Maturity

55โ€“100 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

182 days

Growing Tips for Des Moines 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

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Frequently Asked Questions

When should I plant Cauliflower in Des Moines County, IA?

Des Moines County is in Zone 5b with an average last frost of April 17. Plan your Cauliflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Des Moines County, IA?

Des Moines County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 17 and first fall frost is October 16.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Des Moines County gardeners in Zone 5b 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 Des Moines County, IA. Local conditions may vary. Last updated: April 2026.