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When to plant Corn in Calhoun County County,

Aim to plant Corn in Calhoun County County on or after May 2; the window stays open through May 23. Calhoun County County's 164-day frost-free season gives you a single solid spring crop with a brief fall option.

When to Plant Corn in Calhoun County, IA

Corn

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.

Calhoun County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 6, giving you a growing season of approximately 164 days.

At an elevation of 1,052 feet, Calhoun County receives approximately 30.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Corn to ensure they mature before fall.

Calhoun County, IA (Zone 5a) Moderate season
164 days
Last Spring Frost April 25
164 growing days
First Fall Frost October 6
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Calhoun County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

How Much Corn to Grow

1-2 ears
Average yield per plant
15
Plants per person
30 sq ft
Space per person

For a family of 4, plant approximately 60 corn plants in about 120 sq ft. In Calhoun County's 164-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Monthly Watering Guide for Corn

Corn needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 2.9" 1.4" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.4" 1.9" 💧 Light watering
Oct 4.3" 2.7" 1.6" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

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

Corn Planting Timeline — Calhoun County, IA

Corn Planting Calendar

Activity When Date Range
Direct Sow May 2 May 2 – May 23
Harvest July 4 Jul 4 – Aug 29

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

164 days in Calhoun County

Growing Tips for Calhoun County

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 Calhoun County, IA?

Calhoun County is in Zone 5a with an average last frost of April 25. Plan your Corn planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calhoun County, IA?

Calhoun County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 6.

When should I plant Corn in Calhoun County County, ?

In Calhoun County County, , plant Corn after the last frost (around April 25) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Calhoun County County, for Corn?

Calhoun County 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 Calhoun County County's climate?

Yes — Corn grows well in Calhoun County County's temperate climate. Calhoun County County averages a 164-day frost-free season, with last frost around April 25 and first frost around October 6.

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Your Calhoun County Garden Planner — Free

A 22-page printable planner built for Calhoun 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Calhoun 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.