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When to plant Soybeans in Calhoun County, IA

Soybeans planted in Calhoun County between May 2 and May 23 matures in 80–120 days — well before the October 6 first frost.

When to Plant Soybeans in Calhoun County, IA

Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

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 Soybeans 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

Calhoun County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Monthly Watering Guide for Soybeans

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

Month Soybeans 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.

Soybeans Planting Timeline — Calhoun County, IA

Soybeans Planting Calendar

Activity When Date Range
Direct Sow May 2 May 2 – May 23
Harvest July 25 Jul 25 – Sep 19

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

80–120 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

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Soybeans in Calhoun County, IA?

Calhoun County is in Zone 5a with an average last frost of April 25. Plan your Soybeans 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 Soybeans in Calhoun County, IA?

In Calhoun County, IA, plant Soybeans 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, IA for Soybeans?

Calhoun County sits in USDA Zone 5a. Soybeans grows reliably in zones 3a through 10b, so it's a good fit here.

Can Soybeans grow in Calhoun County's climate?

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

🌱

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

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