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When to Plant Green Beans in Cowlitz County, WA

Green beans are a warm-season staple available as bush or pole types. Bush beans produce a concentrated harvest while pole beans provide a longer picking season.

Cowlitz County, Washington is in USDA Zone 8a. The average last spring frost is April 15 and the first fall frost is October 29, giving you a growing season of approximately 197 days.

At an elevation of 268 feet, Cowlitz County receives approximately 47.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Green Beans during the growing season.

Cowlitz County, WA (Zone 8a) Moderate season
197 days
Last Spring Frost April 15
197 growing days
First Fall Frost October 29

Cowlitz County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (82 days to spare)
Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 30
Recommended (50%) ✓ Fits season (85 days to spare)
Transplant: Apr 15 🍅 Harvest: Jun 10 – Aug 5
Safe Start (90%) ✓ Fits season (89 days to spare)
Transplant: May 7 🍅 Harvest: Jul 2 – Aug 27

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 Cowlitz County

How your county's soil matches Green Beans's growing requirements.

Soil pH

Your soil pH (5.7โ€“6.5) overlaps with Green Beans's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) โ€” Green Beans will thrive.

How to Plant Green Beans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Green Beans

4
successive plantings in your 197-day season

Sow every 5.7 weeks. Last sowing by Aug 25 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Green Beans

Green Beans needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Green Beans Needs Rainfall You Supplement Action
Jan โ€” 7.2" 0" โ„๏ธ Dormant
Feb โ€” 4.6" 0" โ„๏ธ Dormant
Mar โ€” 5.1" 0" โ„๏ธ Dormant
Apr 3.9" 3.6" 0.3" ๐Ÿ’ง Light watering
May 3.9" 2.9" 1" ๐Ÿ’ง Light watering
Jun 3.9" 2" 1.9" ๐Ÿ’ง Light watering
Jul 3.9" 0.8" 3.1" ๐Ÿšฟ Regular watering
Aug 3.9" 0.9" 3" ๐Ÿšฟ Regular watering
Sep 3.9" 1.6" 2.3" ๐Ÿšฟ Regular watering
Oct 3.9" 3.4" 0.5" ๐Ÿ’ง Light watering
Nov โ€” 7.6" 0" โ„๏ธ Dormant
Dec โ€” 7.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Cowlitz County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Green 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.

Green Beans needs ~877 GDD — county provides 3,004 GDD Excellent fit

Green Beans Planting Timeline โ€” Cowlitz County, WA

Green Beans Planting Calendar

Activity When Date Range
Direct Sow April 22 Apr 22 โ€“ May 13
Harvest June 17 Jun 17 โ€“ Aug 12

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

50โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 8a

๐Ÿ“† Growing Season

197 days in Cowlitz County

Growing Tips for Green Beans in Cowlitz County

Direct sow Green Beans outdoors after April 15 in Cowlitz County when soil has warmed and frost danger has passed.

Common pests for Green Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost when soil is warm. Provide sturdy supports for pole varieties. Pick beans regularly when young and tender to encourage continued production.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

๐ŸŒพ Save Your Own Green Beans Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Allow pods to dry fully on vine until they rattle.
Storage Store airtight; viable 4 years at 35ยฐF, under 45% humidity.

Avoid harvesting during damp weather. Isolate 25 ft between varieties.

Frequently Asked Questions

When should I plant Green Beans in Cowlitz County, WA?

Cowlitz County is in Zone 8a with an average last frost of April 15. Plan your Green Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Cowlitz County, WA?

Cowlitz County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 15 and first fall frost is October 29.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Cowlitz County gardeners in Zone 8a 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 Cowlitz County, WA. Local conditions may vary. Last updated: April 2026.