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When to Plant Scarlet Runner Beans in Spink County, SD

Spink County, South Dakota Zone 4b May

Your May planting checklist for Spink County, South Dakota

May is a pivotal month for Spink County, South Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 10
Avg. first frost October 1
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Get scarlet runner beans in the ground

    Your last frost (May 10) has passed. These warm-season crops can handle outdoor soil now.

  2. Sow scarlet runner beans where they'll grow

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Spink County, South Dakota is in USDA Zone 4b. The average last spring frost is May 10 and the first fall frost is October 1, giving you a growing season of approximately 144 days.

At an elevation of 818 feet, Spink County receives approximately 31.4 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall.

Spink County, SD (Zone 4b) Short season
144 days
Last Spring Frost May 10
144 growing days
First Fall Frost October 1
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Spink County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Feb 27 Transplant: May 22 🍅 Harvest: Jul 24 – Aug 28
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 8 Transplant: May 31 🍅 Harvest: Aug 2 – Sep 6
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: Mar 17 Transplant: Jun 9 🍅 Harvest: Aug 11 – Sep 15

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 Spink County

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

Soil pH

Your soil pH (6.7–7.3) overlaps with Scarlet Runner Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Spink 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 (3.4%). 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

2
successive plantings in your 144-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 591 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 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.6" 0.7" 💧 Light watering
Aug 4.3" 4.1" 0.2" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Spink 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 ~752 GDD — county provides 1,548 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Spink County, SD

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest August 2 Aug 2 – Sep 6

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 Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

144 days in Spink County

Growing Tips for Scarlet Runner Beans in Spink County

Direct sow Scarlet Runner Beans outdoors after May 10 in Spink 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 Spink County, SD?

Spink County is in Zone 4b with an average last frost of May 10. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Spink County, SD?

Spink County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 10 and first fall frost is October 1.

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Your Spink County Garden Planner — Free

A 24-page printable planner built for Spink County (Zone 4b). 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 Spink County, SD. 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.