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When to Plant Cowpeas in Okanogan County, WA

Okanogan County, Washington Zone 6b April

Your April game plan for Okanogan County, Washington

Welcome to April in Zone 6b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 13
Avg. first frost September 26
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 13.4 hrs
Coming up in May — start thinking about
  • Direct-sowing: cowpeas

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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.

Okanogan County, Washington is in USDA Zone 5b. The average last spring frost is May 13 and the first fall frost is September 26, giving you a growing season of approximately 136 days.

At an elevation of 3,788 feet, Okanogan County receives approximately 21.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Cowpeas to ensure they mature before fall.

Okanogan County, WA (Zone 5b) Short season
136 days
Last Spring Frost May 13
136 growing days
First Fall Frost September 26
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Okanogan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Transplant: May 8 🍅 Harvest: Jul 10 – Aug 21
Recommended (50%) ✓ Fits season (31 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 26
Safe Start (90%) ✓ Fits season (27 days to spare)
Transplant: Jun 6 🍅 Harvest: Aug 8 – 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 Okanogan County

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

Soil pH

Your soil pH (5.4–6.5) overlaps with Cowpeas's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Cowpeas.

Organic Matter

Organic matter is excellent (5.6%) — Cowpeas will thrive.

How to Plant Cowpeas

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

Succession Planting Cowpeas

2
successive plantings in your 136-day season

Sow every 6.9 weeks. Last sowing by Jun 28 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 2.9" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.3" 0.9" 💧 Light watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.7" 1.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 3.6" 0" ❄️ Dormant
Dec 3.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Okanogan 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 ~919 GDD — county provides 1,666 GDD Excellent fit

Cowpeas Planting Timeline — Okanogan County, WA

Cowpeas Planting Calendar

Activity When Date Range
Direct Sow May 20 May 20 – Jun 10
Harvest July 22 Jul 22 – Sep 2

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 Harvest
October
November
December
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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: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

136 days in Okanogan County

Growing Tips for Cowpeas in Okanogan County

Direct sow Cowpeas outdoors after May 13 in Okanogan 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.

Okanogan County receives only 21" 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 Okanogan County, WA?

Okanogan County is in Zone 5b with an average last frost of May 13. Plan your Cowpeas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Okanogan County, WA?

Okanogan County, Washington is in USDA Hardiness Zone 5b. The average last spring frost is May 13 and first fall frost is September 26.

🌱

Your Okanogan County Garden Planner — Free

A 24-page printable planner built for Okanogan County (Zone 5b). 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 Okanogan County, WA. 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.