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When to Plant Blueberries in Dunn County, WI

Blueberries are long-lived shrubs producing sweet, antioxidant-rich berries. They require acidic soil and are attractive ornamental plants with fall color and spring flowers.

Dunn County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is September 29, giving you a growing season of approximately 140 days.

At an elevation of 1,221 feet, Dunn County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Blueberries to ensure they mature before fall.

Dunn County, WI (Zone 4a) Short season
140 days
Last Spring Frost May 12
140 growing days
First Fall Frost September 29

Dunn County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 31
Recommended (50%) ✓ Fits season
Transplant: Jun 9
Safe Start (90%) ✓ Fits season
Transplant: Jun 17

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
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Blueberries needs ~9,809 GDD — county provides 1,505 GDD May not mature

Blueberries Planting Timeline โ€” Dunn County, WI

Blueberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 9 Jun 9 โ€“ Jun 23

ยท 48" apart ยท Rows 72" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

730โ€“1095 days

Soil pH

4.5 โ€“ 5.5

USDA Zone

Zone 4a

Growing Season

140 days

Growing Tips for Dunn County

Plant at least two varieties for cross-pollination. Acidify soil with sulfur or pine needle mulch to maintain pH 4.5-5.5. Protect ripening berries from birds with netting.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Blueberries in Dunn County, WI?

Dunn County is in Zone 4a with an average last frost of May 12. Plan your Blueberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Dunn County, WI?

Dunn County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is September 29.

๐ŸŒฑ

Plan Your Garden with Confidence

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

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Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Dunn County, WI. Local conditions may vary. Last updated: April 2026.