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When to Plant Scarlet Runner Beans in Union County, OR

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.

Union County, Oregon is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is September 26, giving you a growing season of approximately 137 days.

At an elevation of 2,751 feet, Union County receives approximately 23.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86ยฐF, providing good warmth for Scarlet Runner Beans during the growing season.

Union County, OR (Zone 5b) Short season
137 days
Last Spring Frost May 12
137 growing days
First Fall Frost September 26

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 8 Transplant: May 17 🍅 Harvest: Jul 19 – Aug 23
Recommended (50%) ✓ Fits season (25 days to spare)
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Jul 28 – Sep 1
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 13 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 Union County

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

Soil pH

Your soil pH (5.2โ€“6.6) is more acidic than Scarlet Runner Beans prefers (6.0โ€“7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Union County is excellent for Scarlet Runner Beans โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Scarlet Runner Beans.

Organic Matter

Organic matter is excellent (5.6%) โ€” 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 08 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 707 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 โ€” 2.9" 0" โ„๏ธ Dormant
Feb โ€” 2.6" 0" โ„๏ธ Dormant
Mar โ€” 2.3" 0" โ„๏ธ Dormant
Apr โ€” 1.5" 0" โ„๏ธ Dormant
May 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering
Jun 4.3" 0.9" 3.4" ๐Ÿšฟ Regular watering
Jul 4.3" 0.4" 3.9" ๐Ÿšฟ Regular watering
Aug 4.3" 0.5" 3.8" ๐Ÿšฟ Regular watering
Sep 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Oct โ€” 2" 0" โ„๏ธ Dormant
Nov โ€” 3.8" 0" โ„๏ธ Dormant
Dec โ€” 4.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Union County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,015 GDD — county provides 1,986 GDD Excellent fit

Scarlet Runner Beans Planting Timeline โ€” Union County, OR

Scarlet Runner Beans Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 โ€“ Mar 31
Transplant Outdoors May 26 May 26 โ€“ Jun 9
Direct Sow May 19 May 19 โ€“ Jun 9
Harvest July 28 Jul 28 โ€“ Sep 1

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“80 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_acidic

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

137 days in Union County

Growing Tips for Scarlet Runner Beans in Union County

Direct sow Scarlet Runner Beans outdoors after May 12 in Union 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.

Union County receives only 24" of rain annually. Scarlet Runner Beans needs consistent moisture โ€” 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 Union County, OR?

Union County is in Zone 5b with an average last frost of May 12. Plan your Scarlet Runner Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, OR?

Union County, Oregon is in USDA Hardiness Zone 5b. The average last spring frost is May 12 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, OR. Local conditions may vary. Last updated: April 2026.