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When to Plant Peas in Madison County, MT

Madison County, Montana Zone 5a May

What to do in May

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Madison County, Montana.

Avg. last frost June 11
Avg. first frost September 13
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Sow peas where they'll grow

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

Coming up in June — start thinking about
  • Transplants going out: peas

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Peas are a cool-season legume that fixes nitrogen in the soil. Garden peas are shelled, while snap and snow peas are eaten pod and all.

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 Peas 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

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
Start indoors: Apr 29 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 23
Recommended (50%) ✗ May not fit
Start indoors: May 7 Transplant: Jun 11 🍅 Harvest: Aug 6 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: May 18 Transplant: Jun 22 🍅 Harvest: Aug 17 – Oct 12

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 Peas's growing requirements.

Soil pH

Your soil pH (6.6–8.1) overlaps with Peas's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Peas.

Organic Matter

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

How to Plant Peas

1"
Planting Depth
4"
Between Plants
18"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.7″/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 Peas

Peas needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Peas 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 3" 1.4" 1.6" 🚿 Regular watering
Jul 3" 1.7" 1.3" 💧 Light watering
Aug 3" 2.2" 0.8" 💧 Light watering
Sep 3" 1.8" 1.2" 💧 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.

Peas 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.

Peas needs ~625 GDD — county provides 940 GDD Excellent fit

Peas Planting Timeline — Madison County, MT

Peas Planting Calendar

Activity When Date Range
Start Indoors May 7 May 7 – May 21
Transplant Outdoors June 11 Jun 11 – Jun 25
Direct Sow May 28 May 28 – Jun 18
Harvest August 6 Aug 6 – Oct 1
Fall Sowing July 5 Jul 5 – Jul 19

Plant 1" deep · 4" apart · Rows 18" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Start Indoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

55–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

94 days in Madison County

Growing Tips for Peas in Madison County

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

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

General growing tips

Direct sow as early as soil can be worked in spring. Inoculate seeds with rhizobium for best nitrogen fixation. Provide trellising for climbing varieties.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Peas Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let pods dry brown and papery on the vine.
Storage Store airtight; viable 3 years at 35°F, under 45% humidity.

Very easy to save. Self-pollinating means varieties stay true.

Frequently Asked Questions

When should I plant Peas in Madison County, MT?

Madison County is in Zone 5a with an average last frost of June 11. Plan your Peas 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.

Instant PDF download. No spam, unsubscribe any time.

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.