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When to Plant Scarlet Runner Beans in Madison County, IA

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.

Madison County, Iowa is in USDA Zone 5a. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 1,022 feet, Madison County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall.

Madison County, IA (Zone 5a) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Start indoors: Feb 21 Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Recommended (50%) ✓ Fits season (58 days to spare)
Start indoors: Feb 27 Transplant: May 8 🍅 Harvest: Jul 10 – Aug 14
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Jul 25 – Aug 29

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 Madison County

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

Soil pH

Your soil pH (6.3โ€“6.9) is within Scarlet Runner Beans's preferred range (6.0โ€“7.0).

Soil Texture

The silt loam soil in Madison County is excellent for Scarlet Runner Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) โ€” 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 170-day season

Sow every 6.9 weeks. Last sowing by Jul 23 to harvest before frost.

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

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 โ€” 1.9" 0" โ„๏ธ Dormant
Feb โ€” 2" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr 4.3" 4" 0.3" ๐Ÿ’ง Light watering
May 4.3" 5.4" 0" โœ… Rainfall sufficient
Jun 4.3" 5" 0" โœ… Rainfall sufficient
Jul 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Aug 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Sep 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Oct 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Nov โ€” 2.4" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Madison County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~910 GDD — county provides 2,210 GDD Excellent fit

Scarlet Runner Beans Planting Timeline โ€” Madison County, IA

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 โ€“ Mar 13
Transplant Outdoors May 8 May 8 โ€“ May 22
Direct Sow May 1 May 1 โ€“ May 22
Harvest July 10 Jul 10 โ€“ Aug 14

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“80 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

170 days in Madison County

Growing Tips for Scarlet Runner Beans in Madison County

Direct sow Scarlet Runner Beans outdoors after April 24 in Madison 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 Madison County, IA?

Madison County is in Zone 5a with an average last frost of April 24. Plan your Scarlet Runner Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Madison County, IA?

Madison County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 24 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Madison County gardeners in Zone 5a 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 Madison County, IA. Local conditions may vary. Last updated: April 2026.