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When to Plant Cowpeas in Madison County, MT

Madison County, Montana Zone 5a May

Your May planting checklist for Madison County, Montana

We've pulled the most time-sensitive tasks for Madison County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost June 11
Avg. first frost September 13
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
To set up a strong June, finish these tasks
  • 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.

Madison County, Montana is in USDA Zone 5a. The average last spring frost is June 11 and the first fall frost is September 13, giving you a growing season of approximately 94 days.

At an elevation of 6,394 feet, Madison County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Cowpeas to ensure they mature before fall.

Madison County, MT (Zone 5a) Very short season
94 days
Last Spring Frost June 11
94 growing days
First Fall Frost September 13
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Madison County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 3 🍅 Harvest: Aug 5 – Sep 16
Recommended (50%) ✗ May not fit
Transplant: Jun 11 🍅 Harvest: Aug 13 – Sep 24
Safe Start (90%) ✗ May not fit
Transplant: Jun 22 🍅 Harvest: Aug 24 – Oct 5

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 Madison County

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

Soil pH

Your soil pH (6.6–8.1) is more alkaline than Cowpeas prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Cowpeas.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Cowpeas.

How to Plant Cowpeas

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

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 2.3" 0" ❄️ Dormant
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 2.2" 0" ✅ Rainfall sufficient
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Madison 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 ~750 GDD — county provides 940 GDD Good fit

Cowpeas Planting Timeline — Madison County, MT

Cowpeas Planting Calendar

Activity When Date Range
Direct Sow June 18 Jun 18 – Jul 9
Harvest August 20 Aug 20 – Oct 1

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Direct Sow
July Direct Sow
August Harvest
September Harvest
October Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

94 days in Madison County

Growing Tips for Cowpeas in Madison County

Direct sow Cowpeas outdoors after June 11 in Madison County when soil has warmed and frost danger has passed.

Your 94.0-day growing season in Madison County is tight for Cowpeas (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Madison 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 Madison County, MT?

Madison County is in Zone 5a with an average last frost of June 11. Plan your Cowpeas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, MT?

Madison County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 11 and first fall frost is September 13.

🌱

Your Madison County Garden Planner — Free

A 24-page printable planner built for Madison County (Zone 5a). 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 Madison County, MT. 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.