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When to Plant Cilantro in Marion County, IA

Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Marion County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 7, giving you a growing season of approximately 159 days.

At an elevation of 971 feet, Marion County receives approximately 33.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Cilantro to ensure they mature before fall.

Marion County, IA (Zone 5a) Moderate season
159 days
Last Spring Frost May 1
159 growing days
First Fall Frost October 7

Marion County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Start indoors: Mar 18 Transplant: Apr 15 🍅 Harvest: May 27 – Jul 29
Recommended (50%) ✓ Fits season (61 days to spare)
Start indoors: Mar 27 Transplant: Apr 24 🍅 Harvest: Jun 5 – Aug 7
Safe Start (90%) ✓ Fits season (61 days to spare)
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jun 19 – Aug 21

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
0.1″/week
Watering frequency Only during dry spells
Season total 174 gal / 100 sq ft
Cilantro needs ~650 GDD — county provides 2,067 GDD Excellent fit

Cilantro Planting Timeline โ€” Marion County, IA

Cilantro Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 โ€“ Apr 10
Transplant Outdoors April 24 Apr 24 โ€“ May 8
Direct Sow April 17 Apr 17 โ€“ May 8
Fall Sowing July 29 Jul 29 โ€“ Aug 12
Harvest June 5 Jun 5 โ€“ Aug 7

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

40โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

159 days

Growing Tips for Marion County

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Level Up Your Garden

Frequently Asked Questions

When should I plant Cilantro in Marion County, IA?

Marion County is in Zone 5a with an average last frost of May 1. Plan your Cilantro planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marion County, IA?

Marion County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Marion 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 Marion County, IA. Local conditions may vary. Last updated: April 2026.