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When to plant Radish in Calhoun County, IA

Calhoun County sits in USDA Zone 5a. Plant Radish between April 11 (after last frost on April 25) and May 2. A second sowing from July 28 to August 11 extends the harvest into fall.

When to Plant Radish in Calhoun County, IA

Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

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 Radish 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

6.0-7.0

Drainage

Well Drained

Radish Planting Timeline — Calhoun County, IA

Radish Planting Calendar

Activity When Date Range
Direct Sow April 11 Apr 11 – May 2
Harvest May 9 May 9 – May 30
Fall Sowing July 28 Jul 28 – Aug 11

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

22–35 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 every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in Calhoun County, IA?

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

In Calhoun County, IA, plant Radish 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 Radish?

Calhoun County sits in USDA Zone 5a. Radish grows reliably in zones 2a through 11b, so it's a good fit here.

Can Radish grow in Calhoun County's climate?

Yes — Radish 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.

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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 Calhoun County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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