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When to Plant Scarlet Runner Beans in Slope County, ND

Slope County, North Dakota Zone 4b May

Your May gardening checklist

Your garden in Slope County, North Dakota is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 15
Avg. first frost September 24
Soil temp (4") 52°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Sow scarlet runner beans where they'll grow

    Your soil is 52°F — warm enough for these to germinate without babying.

A few tasks this May that'll pay off in June
  • Transplants going out: 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.

Slope County, North Dakota is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 24, giving you a growing season of approximately 132 days.

At an elevation of 1,230 feet, Slope County receives approximately 31.4 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall.

Slope County, ND (Zone 4b) Short season
132 days
Last Spring Frost May 15
132 growing days
First Fall Frost September 24
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Slope County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 8
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Mar 13 Transplant: Jun 5 🍅 Harvest: Aug 7 – Sep 11
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Mar 30 Transplant: Jun 22 🍅 Harvest: Aug 24 – Sep 28

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 Slope County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Scarlet Runner Beans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Slope 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 (4.2%) — 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 132-day season

Sow every 6.9 weeks. Last sowing by Jul 06 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 424 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.4" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 2.3" 2" 💧 Light watering
Jul 4.3" 3.1" 1.2" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 2.7" 0" ❄️ Dormant
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Slope 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 ~700 GDD — county provides 1,320 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Slope County, ND

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors June 5 Jun 5 – Jun 19
Direct Sow May 29 May 29 – Jun 19
Harvest August 7 Aug 7 – Sep 11

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
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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: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

132 days in Slope County

Growing Tips for Scarlet Runner Beans in Slope County

Direct sow Scarlet Runner Beans outdoors after May 15 in Slope 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 Slope County, ND?

Slope County is in Zone 4b with an average last frost of May 15. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Slope County, ND?

Slope County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 24.

🌱

Your Slope County Garden Planner — Free

A 24-page printable planner built for Slope 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 Slope County, ND. 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.