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When to Plant Scarlet Runner Beans in Darlington County, SC

Darlington County, South Carolina Zone 8b May

Top priorities for Darlington County, South Carolina gardeners in May

We've pulled the most time-sensitive tasks for Darlington County, South Carolina this May and put them front and centre. Tackle them in order.

Avg. last frost March 23
Avg. first frost November 6
Soil temp (4") 73°F
Watering Low
Pest pressure High
Daylight 13.8 hrs
  1. Time to start scarlet runner beans inside

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

June will be here before you know it — start on
  • 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.

Darlington County, South Carolina is in USDA Zone 8b. The average last spring frost is March 23 and the first fall frost is November 6, giving you a growing season of approximately 228 days.

At an elevation of 307 feet, Darlington County receives approximately 54 inches of rainfall annually with predominantly clay loam soil. Summer highs average 93°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.

Darlington County, SC (Zone 8b) Long season
228 days
Last Spring Frost March 23
228 growing days
First Fall Frost November 6
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Darlington County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (119 days to spare)
Start indoors: Jan 26 Transplant: Mar 30 🍅 Harvest: Jun 1 – Jul 6
Recommended (50%) ✓ Fits season (116 days to spare)
Start indoors: Feb 2 Transplant: Apr 6 🍅 Harvest: Jun 8 – Jul 13
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 Darlington County

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

Soil pH

Your soil pH (5.6–6.3) is more acidic than Scarlet Runner Beans prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). 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 228-day season

Sow every 6.9 weeks. Last sowing by Aug 18 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 11 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 4.7" 0" ❄️ Dormant
Feb 4.6" 0" ❄️ Dormant
Mar 4.3" 5.5" 0" ✅ Rainfall sufficient
Apr 4.3" 3.5" 0.8" 💧 Light watering
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 4.5" 0" ✅ Rainfall sufficient
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 4.3" 4.6" 0" ✅ Rainfall sufficient
Dec 4.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Darlington 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 ~1,382 GDD — county provides 4,503 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Darlington County, SC

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 – Feb 16
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 30 Mar 30 – Apr 20
Harvest June 8 Jun 8 – Jul 13

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

Month-by-Month Timeline

MonthActivities
January
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 · Only during dry spells

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

228 days in Darlington County

Growing Tips for Scarlet Runner Beans in Darlington County

Direct sow Scarlet Runner Beans outdoors after March 23 in Darlington County when soil has warmed and frost danger has passed.

With Darlington County's clay soil (33% 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 Darlington County, SC?

Darlington County is in Zone 8b with an average last frost of March 23. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Darlington County, SC?

Darlington County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 23 and first fall frost is November 6.

🌱

Your Darlington County Garden Planner — Free

A 24-page printable planner built for Darlington 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 Darlington 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.