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When to Plant Raspberries in Decatur County, IA

Decatur County, Iowa Zone 5b April

This month in Decatur County, Iowa

Each item below is timed to Decatur County, Iowa's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 23
Avg. first frost October 12
Soil temp (4") 44°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
A few tasks this April that'll pay off in May
  • Transplants going out: raspberries

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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.

Decatur County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.

At an elevation of 541 feet, Decatur County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Raspberries to ensure they mature before fall.

Decatur County, IA (Zone 5b) Moderate season
172 days
Last Spring Frost April 23
172 growing days
First Fall Frost October 12

Decatur County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 8
Recommended (50%) ✓ Fits season
Transplant: May 14
Safe Start (90%) ✓ Fits season
Transplant: Jun 1

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 Decatur County

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

Soil pH

Your soil pH (6.0–7.3) is more alkaline than Raspberries prefers (5.5–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The silt loam soil in Decatur County is excellent for Raspberries — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Raspberries.

Organic Matter

Organic matter is excellent (4.2%) — Raspberries will thrive.

How to Plant Raspberries

24"
Between Plants
72"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 532 gal / 100 sq ft

Monthly Watering Guide for Raspberries

Raspberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Raspberries Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Decatur County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Raspberries Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Raspberries needs ~6,707 GDD — county provides 2,107 GDD May not mature

Raspberries Planting Timeline — Decatur County, IA

Raspberries Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 – May 28

· 24" apart · Rows 72" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

172 days in Decatur County

Growing Tips for Raspberries in Decatur County

Direct sow Raspberries outdoors after April 23 in Decatur County when soil has warmed and frost danger has passed.

Your 172.0-day growing season in Decatur County is tight for Raspberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Raspberries in Decatur County, IA?

Decatur County is in Zone 5b with an average last frost of April 23. Plan your Raspberries planting based on this frost date — see the calendar above for exact timing.

What planting zone is Decatur County, IA?

Decatur County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 12.

🌱

Your Decatur County Garden Planner — Free

A 24-page printable planner built for Decatur County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.