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When to Plant Snap Peas in Flathead County, MT

Flathead County, Montana Zone 5a May

Your May game plan for Flathead County, Montana

Welcome to May in Zone 5a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost June 3
Avg. first frost September 10
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 15 hrs
Get ahead of June
  • Transplants going out: snap peas
  • Direct-sowing: snap peas

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Snap peas have edible pods with plump, sweet peas inside, combining the best features of snow peas and garden peas. They are a garden favorite for fresh eating.

Flathead County, Montana is in USDA Zone 5a. The average last spring frost is June 3 and the first fall frost is September 10, giving you a growing season of approximately 99 days.

At an elevation of 6,233 feet, Flathead County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Snap Peas during the growing season.

Flathead County, MT (Zone 5a) Very short season
99 days
Last Spring Frost June 3
99 growing days
First Fall Frost September 10

Flathead County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 27 Transplant: Jun 5 🍅 Harvest: Jul 31 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Apr 8 Transplant: Jun 17 🍅 Harvest: Aug 12 – Oct 7
Safe Start (90%) ✗ May not fit
Start indoors: Apr 27 Transplant: Jul 6 🍅 Harvest: Aug 31 – Oct 26

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 Flathead County

How your county's soil matches Snap Peas's growing requirements.

Soil pH

Your soil pH (6.6–8.4) overlaps with Snap Peas's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Snap Peas.

How to Plant Snap Peas

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

Succession Planting Snap Peas

2
successive plantings in your 99-day season

Sow every 6.3 weeks. Last sowing by Jul 02 to harvest before frost.

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 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Snap Peas

Snap 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 Snap Peas Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 2.7" 0" ❄️ Dormant
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 1.5" 1.5" 🚿 Regular watering
Aug 3" 2.1" 0.9" 💧 Light watering
Sep 3" 1.5" 1.5" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Snap 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.

Snap Peas needs ~953 GDD — county provides 1,509 GDD Excellent fit

Snap Peas Planting Timeline — Flathead County, MT

Snap Peas Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors June 17 Jun 17 – Jul 1
Direct Sow June 10 Jun 10 – Jul 1
Harvest August 12 Aug 12 – Oct 7

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
June Transplant Outdoors Direct Sow
July Transplant Outdoors Direct Sow
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

99 days in Flathead County

Growing Tips for Snap Peas in Flathead County

Direct sow Snap Peas outdoors after June 03 in Flathead County when soil has warmed and frost danger has passed.

Common pests for Snap 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 in early spring as soon as soil can be worked. Provide a trellis 4-6 feet tall. Harvest when pods are plump and snap cleanly when bent.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Snap Peas in Flathead County, MT?

Flathead County is in Zone 5a with an average last frost of June 3. Plan your Snap Peas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Flathead County, MT?

Flathead County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 3 and first fall frost is September 10.

🌱

Your Flathead County Garden Planner — Free

A 24-page printable planner built for Flathead 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 Flathead 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.