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When to Plant Cilantro in Monona County, IA

Monona County, Iowa Zone 5a April

April in Monona County, Iowa — your action list

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Monona County, Iowa.

Avg. last frost April 26
Avg. first frost October 10
Soil temp (4") 44°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Transplant cilantro outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Put cilantro seeds straight in the ground

    Your soil is 44°F — warm enough for these to germinate without babying.

A few tasks this April that'll pay off in May
  • Starting indoors: cilantro
  • First harvests: cilantro

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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.

Monona County, Iowa is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 10, giving you a growing season of approximately 167 days.

At an elevation of 732 feet, Monona County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Cilantro to ensure they mature before fall.

Monona County, IA (Zone 5a) Moderate season
167 days
Last Spring Frost April 26
167 growing days
First Fall Frost October 10

Monona County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (67 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: May 26 – Jul 28
Recommended (50%) ✓ Fits season (69 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: May 31 – Aug 2
Safe Start (90%) ✓ Fits season (65 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 15 – Aug 17

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.

Soil Compatibility in Monona County

How your county's soil matches Cilantro's growing requirements.

Soil pH

Your soil pH (5.7–7.1) overlaps with Cilantro's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Monona County is excellent for Cilantro — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Cilantro.

Organic Matter

Organic matter is excellent (4.4%) — Cilantro will thrive.

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Cilantro

4
successive plantings in your 167-day season

Sow every 4.6 weeks. Last sowing by Aug 11 to harvest before frost.

For a dedicated fall crop, sow by Aug 01.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 4.3" 0" ✅ Rainfall sufficient
Jul 2.2" 4" 0" ✅ Rainfall sufficient
Aug 2.2" 4.2" 0" ✅ Rainfall sufficient
Sep 2.2" 2.8" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monona County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cilantro Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Cilantro needs ~612 GDD — county provides 2,045 GDD Excellent fit

Cilantro Planting Timeline — Monona County, IA

Cilantro Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 12 Apr 12 – May 3
Harvest May 31 May 31 – Aug 2
Fall Sowing August 1 Aug 1 – Aug 15

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

167 days in Monona County

Growing Tips for Cilantro in Monona County

Direct sow Cilantro outdoors after April 26 in Monona County when soil has warmed and frost danger has passed.

Your generous 167.0-day season in Monona County allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Monona County, IA?

Monona County is in Zone 5a with an average last frost of April 26. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monona County, IA?

Monona County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 10.

🌱

Your Monona County Garden Planner — Free

A 24-page printable planner built for Monona County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Monona County, IA. Local conditions may vary. Last updated: April 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.