Blog

When to Plant Raspberries in Grundy County, IA

Raspberries are beloved bramble fruits producing sweet, delicate berries in red, golden, black, and purple varieties. They spread by underground runners and are very productive.

Grundy County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 9, giving you a growing season of approximately 164 days.

At an elevation of 984 feet, Grundy County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Raspberries to ensure they mature before fall.

Grundy County, IA (Zone 5a) Moderate season
164 days
Last Spring Frost April 28
164 growing days
First Fall Frost October 9

Grundy County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 13
Recommended (50%) ✓ Fits season
Transplant: May 19
Safe Start (90%) ✓ Fits season
Transplant: Jun 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.

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 331 gal / 100 sq ft
Raspberries needs ~6,707 GDD — county provides 2,009 GDD May not mature

Raspberries Planting Timeline โ€” Grundy County, IA

Raspberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 19 May 19 โ€“ Jun 2

ยท 24" 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

365โ€“730 days

Soil pH

5.5 โ€“ 6.5

USDA Zone

Zone 5a

Growing Season

164 days

Growing Tips for Grundy County

Provide a trellis for support. Prune summer-bearing types by removing spent canes after harvest. For ever-bearing types, mow all canes in late winter for a single fall crop.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Tomatoes

Level Up Your Garden

Frequently Asked Questions

When should I plant Raspberries in Grundy County, IA?

Grundy County is in Zone 5a with an average last frost of April 28. Plan your Raspberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Grundy County, IA?

Grundy County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Grundy County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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 Grundy County, IA. Local conditions may vary. Last updated: April 2026.