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When to Plant Scarlet Runner Beans in Marion County, SC

Marion County, South Carolina Zone 8b May

May to-do list for Marion County, South Carolina

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Marion County, South Carolina.

Avg. last frost March 21
Avg. first frost November 10
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Start scarlet runner beans indoors

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

June prep starts now
  • First harvests: 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.

Marion County, South Carolina is in USDA Zone 8b. The average last spring frost is March 21 and the first fall frost is November 10, giving you a growing season of approximately 234 days.

At an elevation of 175 feet, Marion County receives approximately 51.5 inches of rainfall annually with predominantly clay loam soil. Summer highs average 94°F, providing good warmth for Scarlet Runner Beans during the growing season. Clay soil retains moisture well for Scarlet Runner Beans, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Scarlet Runner Beans root diseases.

Marion County, SC (Zone 8b) Long season
234 days
Last Spring Frost March 21
234 growing days
First Fall Frost November 10
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Marion County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (126 days to spare)
Start indoors: Jan 20 Transplant: Mar 24 🍅 Harvest: May 26 – Jun 30
Recommended (50%) ✓ Fits season (122 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jun 6 – Jul 11
Safe Start (90%) ✓ Fits season (115 days to spare)
Start indoors: Feb 20 Transplant: Apr 24 🍅 Harvest: Jun 26 – Jul 31

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 Marion County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Scarlet Runner Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Scarlet Runner Beans.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Scarlet Runner Beans.

How to Plant Scarlet Runner Beans

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

Succession Planting Scarlet Runner Beans

4
successive plantings in your 234-day season

Sow every 6.9 weeks. Last sowing by Aug 22 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 4.6" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.3" 5.3" 0" ✅ Rainfall sufficient
Apr 4.3" 4.2" 0.1" 💧 Light watering
May 4.3" 4.2" 0.1" 💧 Light watering
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 5.5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.9" 0.4" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 4.3" 3.3" 1" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Marion 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 ~1,435 GDD — county provides 4,797 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Marion County, SC

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors January 31 Jan 31 – Feb 14
Transplant Outdoors April 4 Apr 4 – Apr 18
Direct Sow March 28 Mar 28 – Apr 18
Harvest June 6 Jun 6 – Jul 11

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

234 days in Marion County

Growing Tips for Scarlet Runner Beans in Marion County

Direct sow Scarlet Runner Beans outdoors after March 21 in Marion County when soil has warmed and frost danger has passed.

With Marion County's clay soil (30% clay), work in 3-4 inches of compost before planting Scarlet Runner Beans. Avoid tilling when soil is wet to prevent compaction.

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 Marion County, SC?

Marion County is in Zone 8b with an average last frost of March 21. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marion County, SC?

Marion County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 21 and first fall frost is November 10.

🌱

Your Marion County Garden Planner — Free

A 24-page printable planner built for Marion County (Zone 8b). 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 Marion County, SC. Local conditions may vary. Last updated: May 2026.

Sources & credits

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