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When to Plant Blueberries in Watonwan County, MN

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.

Watonwan County, Minnesota is in USDA Zone 4b. The average last spring frost is April 29 and the first fall frost is October 6, giving you a growing season of approximately 160 days.

At an elevation of 984 feet, Watonwan County receives approximately 33.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Blueberries to ensure they mature before fall.

Watonwan County, MN (Zone 4b) Moderate season
160 days
Last Spring Frost April 29
160 growing days
First Fall Frost October 6

Watonwan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 22
Recommended (50%) ✓ Fits season
Transplant: May 27
Safe Start (90%) ✓ Fits season
Transplant: Jun 11

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 157 gal / 100 sq ft
Blueberries needs ~10,494 GDD — county provides 1,840 GDD May not mature

Blueberries Planting Timeline โ€” Watonwan County, MN

Blueberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 27 May 27 โ€“ Jun 10

ยท 48" apart ยท Rows 72" 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

Moderate โ€” regular watering

Days to Maturity

730โ€“1095 days

Soil pH

4.5 โ€“ 5.5

USDA Zone

Zone 4b

Growing Season

160 days

Growing Tips for Watonwan 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 Watonwan County, MN?

Watonwan County is in Zone 4b with an average last frost of April 29. Plan your Blueberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Watonwan County, MN?

Watonwan County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 29 and first fall frost is October 6.

๐ŸŒฑ

Plan Your Garden with Confidence

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