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When to Plant Snap Peas in Yellowstone County, MT

Yellowstone County, Montana Zone 5a May

Yellowstone County, Montana gardeners: here's your May plan

A quick May briefing for Yellowstone County, Montana gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 9
Avg. first frost October 3
Soil temp (4") 33°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Move snap peas into the garden

    Frost risk is low now in Yellowstone County, Montana. If you've been covering beds overnight, you can stop.

  2. Sow snap peas where they'll grow

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Yellowstone County, Montana is in USDA Zone 5a. The average last spring frost is May 9 and the first fall frost is October 3, giving you a growing season of approximately 147 days.

At an elevation of 7,432 feet, Yellowstone County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Snap Peas to ensure they mature before fall.

Yellowstone County, MT (Zone 5a) Short season
147 days
Last Spring Frost May 9
147 growing days
First Fall Frost October 3
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Yellowstone County Soil Profile

Soil Type

Loam

Soil pH

6.2-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 9 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 7
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Jul 18 – Sep 12
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Mar 27 Transplant: Jun 5 🍅 Harvest: Jul 31 – Sep 25

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 Yellowstone County

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

Soil pH

Your soil pH (6.2–8.0) overlaps with Snap Peas's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Snap Peas.

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

3
successive plantings in your 147-day season

Sow every 6.3 weeks. Last sowing by Jul 25 to harvest before frost.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 482 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 1.3" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 3" 2.7" 0.3" 💧 Light watering
Jun 3" 1.7" 1.3" 💧 Light watering
Jul 3" 1.7" 1.3" 💧 Light watering
Aug 3" 2.5" 0.5" 💧 Light watering
Sep 3" 1.7" 1.3" 💧 Light watering
Oct 3" 1.8" 1.2" 💧 Light watering
Nov 1.6" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Yellowstone 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 ~625 GDD — county provides 1,470 GDD Excellent fit

Snap Peas Planting Timeline — Yellowstone County, MT

Snap Peas Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Harvest July 18 Jul 18 – Sep 12

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

55–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

147 days in Yellowstone County

Growing Tips for Snap Peas in Yellowstone County

Direct sow Snap Peas outdoors after May 09 in Yellowstone 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 Yellowstone County, MT?

Yellowstone County is in Zone 5a with an average last frost of May 9. Plan your Snap Peas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yellowstone County, MT?

Yellowstone County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is May 9 and first fall frost is October 3.

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Your Yellowstone County Garden Planner — Free

A 24-page printable planner built for Yellowstone 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 Yellowstone 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.