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When to Plant Cowpeas in Yakima County, WA

Yakima County, Washington Zone 7a May

Yakima County, Washington gardeners: here's your May plan

Each item below is timed to Yakima County, Washington's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 6
Avg. first frost October 3
Soil temp (4") 54°F
Watering Critical
Pest pressure Low
Daylight 14.8 hrs
  1. Scatter cowpeas into prepared beds

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

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Cowpeas (black-eyed peas) are a heat-loving legume that fixes nitrogen in the soil. They are drought-tolerant and produce protein-rich pods in hot conditions.

Yakima County, Washington is in USDA Zone 7a. The average last spring frost is May 6 and the first fall frost is October 3, giving you a growing season of approximately 150 days.

At an elevation of 3,150 feet, Yakima County receives approximately 18 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Cowpeas during the growing season. With low rainfall, drip irrigation is essential for growing Cowpeas successfully. Mulch heavily to conserve soil moisture.

Yakima County, WA (Zone 7a) Moderate season
150 days
Last Spring Frost May 6
150 growing days
First Fall Frost October 3

Yakima County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (45 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 13
Recommended (50%) ✓ Fits season (45 days to spare)
Transplant: May 6 🍅 Harvest: Jul 8 – Aug 19
Safe Start (90%) ✓ Fits season (42 days to spare)
Transplant: May 26 🍅 Harvest: Jul 28 – Sep 8

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 Yakima County

How your county's soil matches Cowpeas's growing requirements.

Soil pH

Your soil pH (5.5–6.3) is within Cowpeas's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Yakima County is excellent for Cowpeas — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.8%) — Cowpeas will thrive.

How to Plant Cowpeas

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

Succession Planting Cowpeas

2
successive plantings in your 150-day season

Sow every 6.9 weeks. Last sowing by Jul 05 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Cowpeas

Cowpeas needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cowpeas Needs Rainfall You Supplement Action
Jan 2.6" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.2" 1" 1.2" 🚿 Regular watering
Jun 2.2" 0.6" 1.6" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.6" 1.6" 🚿 Regular watering
Oct 2.2" 1.4" 0.8" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 3.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Yakima County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Cowpeas 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.

Cowpeas needs ~1,088 GDD — county provides 2,175 GDD Excellent fit

Cowpeas Planting Timeline — Yakima County, WA

Cowpeas Planting Calendar

Activity When Date Range
Direct Sow May 13 May 13 – Jun 3
Harvest July 15 Jul 15 – Aug 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

150 days in Yakima County

Growing Tips for Cowpeas in Yakima County

Direct sow Cowpeas outdoors after May 06 in Yakima County when soil has warmed and frost danger has passed.

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

Yakima County receives only 18" of rain annually. Cowpeas needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is thoroughly warm. Do not over-fertilize with nitrogen as cowpeas fix their own. Harvest pods when they begin to dry on the vine for dry beans.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Onion

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cowpeas in Yakima County, WA?

Yakima County is in Zone 7a with an average last frost of May 6. Plan your Cowpeas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yakima County, WA?

Yakima County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 6 and first fall frost is October 3.

🌱

Your Yakima County Garden Planner — Free

A 24-page printable planner built for Yakima County (Zone 7a). 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 Yakima County, WA. 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.