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When to Plant Scarlet Runner Beans in Osceola County, IA

Osceola County, Iowa Zone 5a April

This month in Osceola County, Iowa

Welcome to April in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 1
Avg. first frost October 5
Soil temp (4") 42°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
Before May arrives, get these ready
  • Transplants going out: scarlet runner beans
  • Direct-sowing: scarlet runner beans

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Scarlet runner beans are ornamental and edible climbing beans with vivid red flowers that attract hummingbirds. Both the young pods and mature beans are edible.

Osceola County, Iowa is in USDA Zone 5a. The average last spring frost is May 1 and the first fall frost is October 5, giving you a growing season of approximately 157 days.

At an elevation of 752 feet, Osceola County receives approximately 34.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall.

Osceola County, IA (Zone 5a) Moderate season
157 days
Last Spring Frost May 1
157 growing days
First Fall Frost October 5

Osceola County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Feb 26 Transplant: May 7 🍅 Harvest: Jul 9 – Aug 13
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Jul 17 – Aug 21
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Mar 20 Transplant: May 29 🍅 Harvest: Jul 31 – Sep 4

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 Osceola County

How your county's soil matches Scarlet Runner Beans's growing requirements.

Soil pH

Your soil pH (5.8–6.9) overlaps with Scarlet Runner Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Osceola County is excellent for Scarlet Runner Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Scarlet Runner Beans will thrive.

How to Plant Scarlet Runner Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Scarlet Runner Beans

3
successive plantings in your 157-day season

Sow every 6.9 weeks. Last sowing by Jul 17 to harvest before frost.

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 143 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Scarlet Runner Beans

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

Month Scarlet Runner Beans Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 3.7" 0.6" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Scarlet Runner Beans 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.

Scarlet Runner Beans needs ~700 GDD — county provides 1,570 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Osceola County, IA

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 – Mar 20
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 8 May 8 – May 29
Harvest July 17 Jul 17 – Aug 21

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

157 days in Osceola County

Growing Tips for Scarlet Runner Beans in Osceola County

Direct sow Scarlet Runner Beans outdoors after May 01 in Osceola County when soil has warmed and frost danger has passed.

Common pests for Scarlet Runner Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Provide tall trellising for vigorous vines. Direct sow after frost. Harvest pods young for snap beans or let mature for shelling beans. Tubers are perennial in mild climates.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Scarlet Runner Beans in Osceola County, IA?

Osceola County is in Zone 5a with an average last frost of May 1. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Osceola County, IA?

Osceola County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 1 and first fall frost is October 5.

🌱

Your Osceola County Garden Planner — Free

A 24-page printable planner built for Osceola County (Zone 5a). 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 Osceola 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.