Blog

When to Plant Green Beans in Washington County, IA

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.

Washington County, Iowa is in USDA Zone 5a. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.

At an elevation of 542 feet, Washington County receives approximately 30.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Green Beans to ensure they mature before fall.

Washington County, IA (Zone 5a) Moderate season
176 days
Last Spring Frost April 21
176 growing days
First Fall Frost October 14

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Monthly Watering Guide for Green Beans

Green 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 Green Beans Needs Rainfall You Supplement Action
Jan โ€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1.5" 0" โ„๏ธ Dormant
Mar โ€” 1.9" 0" โ„๏ธ Dormant
Apr 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
May 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Jun 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Jul 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Aug 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Sep 4.3" 2.6" 1.7" ๐Ÿ’ง Light watering
Oct 4.3" 2.6" 1.7" ๐Ÿ’ง Light watering
Nov โ€” 2" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

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

Green Beans Planting Timeline โ€” Washington County, IA

Green Beans Planting Calendar

Activity When Date Range
Direct Sow April 28 Apr 28 โ€“ May 19
Harvest June 23 Jun 23 โ€“ Aug 18

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

Moderate โ€” regular watering

๐Ÿ“… Days to Maturity

50โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

176 days in Washington County

Growing Tips for Washington County

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 Washington County, IA?

Washington County is in Zone 5a with an average last frost of April 21. Plan your Green Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Washington County, IA?

Washington County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 21 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Washington County gardeners in Zone 5a 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 Washington County, IA. Local conditions may vary. Last updated: April 2026.