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When to Plant Cranberries in Iowa County, WI

Cranberries are low-growing, vine-like shrubs that produce tart red berries in fall. They grow in acidic, boggy conditions and are surprisingly easy to cultivate.

Iowa County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 3 and the first fall frost is October 7, giving you a growing season of approximately 157 days.

At an elevation of 602 feet, Iowa County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Cranberries to ensure they mature before fall.

Iowa County, WI (Zone 4b) Moderate season
157 days
Last Spring Frost May 3
157 growing days
First Fall Frost October 7

Iowa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 25
Recommended (50%) ✓ Fits season
Transplant: May 31
Safe Start (90%) ✓ Fits season
Transplant: Jun 18

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 754 gal / 100 sq ft
Cranberries needs ~10,494 GDD — county provides 1,805 GDD May not mature

Cranberries Planting Timeline โ€” Iowa County, WI

Cranberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 31 May 31 โ€“ Jun 14

ยท 36" apart ยท Rows 48" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June Transplant Outdoors
July โ€”
August โ€”
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

730โ€“1095 days

Soil pH

4 โ€“ 5.5

USDA Zone

Zone 4b

Growing Season

157 days

Growing Tips for Iowa County

Create an acidic, consistently moist bed with peat moss. Cranberries do not need to be flooded to grow; flooding is only used for commercial harvesting. Mulch with sand in early spring.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Cranberries in Iowa County, WI?

Iowa County is in Zone 4b with an average last frost of May 3. Plan your Cranberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Iowa County, WI?

Iowa County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 3 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Iowa 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 Iowa County, WI. Local conditions may vary. Last updated: April 2026.