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When to Plant Scarlet Runner Beans in Grand Forks County, ND

Grand Forks County, North Dakota Zone 3b April

Grand Forks County, North Dakota gardeners: here's your April plan

A quick April briefing for Grand Forks County, North Dakota gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 37°F
Watering None
Pest pressure Low
Daylight 13.4 hrs
Looking ahead to May
  • Direct-sowing: 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.

Grand Forks County, North Dakota is in USDA Zone 3b. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 572 feet, Grand Forks County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Scarlet Runner Beans to ensure they mature before fall.

Grand Forks County, ND (Zone 3b) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Grand Forks County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 2 Transplant: May 25 🍅 Harvest: Jul 27 – Aug 31
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Mar 9 Transplant: Jun 1 🍅 Harvest: Aug 3 – Sep 7
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Mar 21 Transplant: Jun 13 🍅 Harvest: Aug 15 – Sep 19

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 Grand Forks County

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

Soil pH

Your soil pH (6.8–7.4) 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 Grand Forks County is excellent for Scarlet Runner Beans — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.3%). 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 142-day season

Sow every 6.9 weeks. Last sowing by Jul 12 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 274 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 0.8" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.6" 0" ✅ Rainfall sufficient
Jul 4.3" 3" 1.3" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 2.5" 1.8" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Grand Forks 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 ~648 GDD — county provides 1,313 GDD Excellent fit

Scarlet Runner Beans Planting Timeline — Grand Forks County, ND

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 25 May 25 – Jun 15
Harvest August 3 Aug 3 – Sep 7

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

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_alkaline

🗺️ USDA Zone

Zone 3b

📆 Growing Season

142 days in Grand Forks County

Growing Tips for Scarlet Runner Beans in Grand Forks County

Direct sow Scarlet Runner Beans outdoors after May 11 in Grand Forks 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 Grand Forks County, ND?

Grand Forks County is in Zone 3b with an average last frost of May 11. Plan your Scarlet Runner Beans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grand Forks County, ND?

Grand Forks County, North Dakota is in USDA Hardiness Zone 3b. The average last spring frost is May 11 and first fall frost is September 30.

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Your Grand Forks County Garden Planner — Free

A 24-page printable planner built for Grand Forks County (Zone 3b). 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 Grand Forks County, ND. Local conditions may vary. Last updated: April 2026.

Sources & credits

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