When to Plant Cowpeas in Stillwater County, MT
Top priorities for Stillwater County, Montana gardeners in May
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
-
Seed cowpeas outdoors
Your soil is 36°F — warm enough for these to germinate without babying.
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.
Stillwater County, Montana is in USDA Zone 5a. The average last spring frost is May 22 and the first fall frost is September 22, giving you a growing season of approximately 123 days.
At an elevation of 6,319 feet, Stillwater County receives approximately 16.6 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Cowpeas to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Cowpeas successfully. Mulch heavily to conserve soil moisture.
Stillwater County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.8
Drainage
Well Drained
Plant Planting Risk Windows
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 Stillwater County
How your county's soil matches Cowpeas's growing requirements.
Soil pH
Your soil pH (6.3–7.8) is more alkaline than Cowpeas prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Stillwater County is excellent for Cowpeas — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Cowpeas.
How to Plant Cowpeas
Succession Planting Cowpeas
Sow every 6.9 weeks. Last sowing by Jun 24 to harvest before frost.
Plant Water Budget
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 | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 1.8" | 0" | ❄️ Dormant |
| May | 2.2" | 2" | 0.2" | 💧 Light watering |
| Jun | 2.2" | 1.1" | 1.1" | 🚿 Regular watering |
| Jul | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Aug | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Sep | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Oct | — | 1.4" | 0" | ❄️ Dormant |
| Nov | — | 1.1" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Stillwater 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 Planting Timeline — Stillwater County, MT
Cowpeas Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 29 | May 29 – Jun 19 |
| Harvest | July 31 | Jul 31 – Sep 11 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow |
| June | Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| 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: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
123 days in Stillwater County
Growing Tips for Cowpeas in Stillwater County
Direct sow Cowpeas outdoors after May 22 in Stillwater 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.
Stillwater County receives only 17" 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
Check more plant combinations with our Companion Planting Checker →
Cowpeas in Other Locations
Frequently Asked Questions
When should I plant Cowpeas in Stillwater County, MT?
Stillwater County is in Zone 5a with an average last frost of May 22. Plan your Cowpeas planting based on this frost date — see the calendar above for exact timing.
What planting zone is Stillwater County, MT?
Stillwater County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 22 and first fall frost is September 22.
Your Stillwater County Garden Planner — Free
A 24-page printable planner built for Stillwater 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.