When to Plant Snap Peas in Lewis and Clark County, MT
What to do 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.
Get ahead of June
- Transplants going out: snap peas
- Direct-sowing: snap peas
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.
Lewis and Clark County, Montana is in USDA Zone 4b. The average last spring frost is May 29 and the first fall frost is September 18, giving you a growing season of approximately 112 days.
At an elevation of 7,064 feet, Lewis and Clark County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Snap Peas to ensure they mature before fall.
Lewis and Clark County Soil Profile
Soil Type
Loam
Soil pH
6.5-8.1
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 Lewis and Clark County
How your county's soil matches Snap Peas's growing requirements.
Soil pH
Your soil pH (6.5–8.1) overlaps with Snap Peas's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Lewis and Clark County is excellent for Snap Peas — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Snap Peas.
How to Plant Snap Peas
Succession Planting Snap Peas
Sow every 6.3 weeks. Last sowing by Jul 10 to harvest before frost.
Plant Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 2.3" | 0" | ❄️ Dormant |
| May | 3" | 2.6" | 0.4" | 💧 Light watering |
| Jun | 3" | 1.5" | 1.5" | 🚿 Regular watering |
| Jul | 3" | 1.9" | 1.1" | 💧 Light watering |
| Aug | 3" | 2.3" | 0.7" | 💧 Light watering |
| Sep | 3" | 1.8" | 1.2" | 💧 Light watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Lewis and Clark 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 Planting Timeline — Lewis and Clark County, MT
Snap Peas Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 27 | Mar 27 – Apr 10 |
| Transplant Outdoors | June 19 | Jun 19 – Jul 3 |
| Direct Sow | June 12 | Jun 12 – Jul 3 |
| Harvest | August 14 | Aug 14 – Oct 9 |
Plant 1" deep · 4" apart · Rows 18" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| 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 4b
📆 Growing Season
112 days in Lewis and Clark County
Growing Tips for Snap Peas in Lewis and Clark County
Direct sow Snap Peas outdoors after May 29 in Lewis and Clark 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
Check more plant combinations with our Companion Planting Checker →
Snap Peas in Other Locations
Frequently Asked Questions
When should I plant Snap Peas in Lewis and Clark County, MT?
Lewis and Clark County is in Zone 4b with an average last frost of May 29. Plan your Snap Peas planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lewis and Clark County, MT?
Lewis and Clark County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 29 and first fall frost is September 18.
Your Lewis and Clark County Garden Planner — Free
A 24-page printable planner built for Lewis and Clark County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.