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When to Plant Daikon in Calhoun County, IA

Daikon is a large, mild Japanese radish that can grow over a foot long. It is excellent for pickling, stir-fries, and as a soil-breaking cover crop.

Calhoun County, Iowa is in USDA Zone 4b. 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 82ยฐF, so choose short-season varieties of Daikon to ensure they mature before fall.

Calhoun County, IA (Zone 4b) 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

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 16 – Jul 14
Recommended (50%) ✓ Fits season (80 days to spare)
Transplant: Apr 25 🍅 Harvest: Jun 20 – Jul 18
Safe Start (90%) ✓ Fits season (80 days to spare)
Transplant: May 10 🍅 Harvest: Jul 5 – Aug 2

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 Calhoun County

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

Soil pH

Your soil pH (5.8โ€“6.8) is within Daikon's preferred range (5.8โ€“7.0).

Soil Texture

The silt loam soil in Calhoun County is excellent for Daikon โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.5%) โ€” Daikon will thrive.

How to Plant Daikon

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Daikon

3
successive plantings in your 164-day season

Sow every 5.7 weeks. Last sowing by Jul 28 to harvest before frost.

For a dedicated fall crop, sow by Jul 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 334 gal / 100 sq ft
Daikon needs ~690 GDD — county provides 1,886 GDD Excellent fit

Daikon Planting Timeline โ€” Calhoun County, IA

Daikon Planting Calendar

Activity When Date Range
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing July 14 Jul 14 โ€“ Jul 28
Harvest June 13 Jun 13 โ€“ Jul 11

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

50โ€“70 days

๐Ÿงช Soil pH

Needs 5.8โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

164 days in Calhoun County

Growing Tips for Daikon in Calhoun County

Direct sow Daikon outdoors after April 25 in Calhoun County when soil has warmed and frost danger has passed.

Common pests for Daikon in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in late summer for fall harvest. Loosen soil deeply before planting. Thin seedlings to 6 inches apart. Harvest before hard freeze as exposed shoulders may crack.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Level Up Your Garden

Frequently Asked Questions

When should I plant Daikon in Calhoun County, IA?

Calhoun County is in Zone 4b with an average last frost of April 25. Plan your Daikon planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Calhoun County, IA?

Calhoun County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 25 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Calhoun County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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: April 2026.