Blog

When to Plant Scarlet Runner Beans in Haakon County, SD

Haakon County, South Dakota Zone 4b May

May in the garden — Haakon County, South Dakota

May is a pivotal month for Haakon 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 14
Avg. first frost September 28
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
  1. Plant scarlet runner beans from seed, right in the garden

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June will be here before you know it — start on
  • Transplants going out: scarlet runner beans

Instant PDF download. No spam, unsubscribe any time.

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.

Haakon County, South Dakota is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.

At an elevation of 1,097 feet, Haakon County receives approximately 22.5 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.

Haakon County, SD (Zone 4b) Short season
137 days
Last Spring Frost May 14
137 growing days
First Fall Frost September 28
Share this guide:

Haakon County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Mar 7 Transplant: May 30 🍅 Harvest: Aug 1 – Sep 5
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 6 – Sep 10
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 22

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 Haakon County

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

Soil pH

Your soil pH (6.5–7.5) overlaps with Scarlet Runner Beans's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Haakon 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 excellent (4.1%) — 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

2
successive plantings in your 137-day season

Sow every 6.9 weeks. Last sowing by Jul 10 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 893 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.6" 2.7" 🚿 Regular watering
Jul 4.3" 1.9" 2.4" 🚿 Regular watering
Aug 4.3" 2.3" 2" 💧 Light watering
Sep 4.3" 2" 2.3" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.8" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Haakon 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 1,472 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Haakon County, SD

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest August 6 Aug 6 – Sep 10

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
September Harvest
October
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

137 days in Haakon County

Growing Tips for Scarlet Runner Beans in Haakon County

Direct sow Scarlet Runner Beans outdoors after May 14 in Haakon 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.

Haakon County receives only 22" of rain annually. Scarlet Runner Beans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Haakon County, SD?

Haakon County is in Zone 4b with an average last frost of May 14. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haakon County, SD?

Haakon County, South Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is September 28.

🌱

Your Haakon County Garden Planner — Free

A 24-page printable planner built for Haakon 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Haakon 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.