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When to Plant Scarlet Runner Beans in Marshall County, IL

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.

Marshall County, Illinois is in USDA Zone 5a. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 1,177 feet, Marshall County receives approximately 30.4 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.

Marshall County, IL (Zone 5a) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (63 days to spare)
Start indoors: Feb 19 Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 6
Recommended (50%) ✓ Fits season (63 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Jul 7 – Aug 11
Safe Start (90%) ✓ Fits season (60 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 Marshall County

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

Soil pH

Your soil pH (6.0โ€“6.8) is within Scarlet Runner Beans's preferred range (6.0โ€“7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) 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 175-day season

Sow every 6.9 weeks. Last sowing by Jul 25 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 505 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Scarlet Runner Beans needs ~910 GDD — county provides 2,275 GDD Excellent fit

Scarlet Runner Beans Planting Timeline โ€” Marshall County, IL

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 โ€“ Mar 10
Transplant Outdoors May 5 May 5 โ€“ May 19
Direct Sow April 28 Apr 28 โ€“ May 19
Harvest July 7 Jul 7 โ€“ Aug 11

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

Month-by-Month Timeline

MonthActivities
January โ€”
February Start Indoors
March Start Indoors
April Direct Sow
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 1-2 times/week

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

175 days in Marshall County

Growing Tips for Scarlet Runner Beans in Marshall County

Direct sow Scarlet Runner Beans outdoors after April 21 in Marshall 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Scarlet Runner Beans in Marshall County, IL?

Marshall County is in Zone 5a with an average last frost of April 21. Plan your Scarlet Runner Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marshall County, IL?

Marshall County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 21 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

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