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When to plant Corn in Monona County County,

Monona County County's climate puts the Corn spring window between May 3 and May 24. time plantings around the expected last-frost window for best survival.

When to Plant Corn in Monona County, IA

Corn
Monona County, Iowa Zone 5a June

Your June gardening checklist

Here's what deserves your attention in Monona County, Iowa this month. Everything below is tailored to Zone 5a and timed around your local frost dates.

Avg. last frost April 26
Avg. first frost October 10
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
Looking ahead to July
  • First harvests: corn

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Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

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 Corn 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

Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (46 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 18
Recommended (50%) ✓ Fits season (48 days to spare)
Transplant: Apr 26 🍅 Harvest: Jun 28 – Aug 23
Safe Start (90%) ✓ Fits season (44 days to spare)
Transplant: May 11 🍅 Harvest: Jul 13 – Sep 7

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 Corn's growing requirements.

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Corn.

Organic Matter

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

How to Plant Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Corn

3
successive plantings in your 167-day season

Sow every 6.9 weeks. Last sowing by Jul 02 to harvest before frost.

Corn 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 1,903 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Corn

Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 6.5" 3" 3.5" 🚿 Regular watering
May 6.5" 3.8" 2.7" 💧 Light watering
Jun 6.5" 4.3" 2.2" 💧 Light watering
Jul 6.5" 4" 2.5" 💧 Light watering
Aug 6.5" 4.2" 2.3" 💧 Light watering
Sep 6.5" 2.8" 3.7" 🚿 Regular watering
Oct 6.5" 3" 3.5" 🚿 Regular watering
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.

Corn 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.

Corn needs ~980 GDD — county provides 2,045 GDD Excellent fit

Corn Planting Timeline — Monona County, IA

Corn Planting Calendar

Activity When Date Range
Direct Sow May 3 May 3 – May 24
Harvest July 5 Jul 5 – Aug 30

Plant 1" deep · 12" apart · Rows 36" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

167 days in Monona County

Growing Tips for Corn in Monona County

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

Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Monona County, IA?

Monona County is in Zone 5a with an average last frost of April 26. Plan your Corn 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.

When should I plant Corn in Monona County, ?

In Monona County, , plant Corn after the last frost (around April 26) and before the first frost (around October 10). Best results when soil holds above 50°F.

What growing zone is Monona County, for Corn?

Monona County sits in USDA Zone 5a. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Monona County's climate?

Yes — Corn grows well in Monona County's temperate climate. Monona County averages a 167-day frost-free season, with last frost around April 26 and first frost around October 10.

🌱

Your Monona County Garden Planner — Free

A 22-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: June 2026.

Sources & credits

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