Blog

When to Plant Peas in Grand County, CO

Grand County, Colorado Zone 5a May

May in the garden — Grand County, Colorado

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

Avg. last frost May 28
Avg. first frost September 19
Soil temp (4") 42°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant peas

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Outdoor sowing time: peas

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

Instant PDF download. No spam, unsubscribe any time.

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.

Grand County, Colorado is in USDA Zone 5a. The average last spring frost is May 28 and the first fall frost is September 19, giving you a growing season of approximately 114 days.

At an elevation of 5,397 feet, Grand County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Peas to ensure they mature before fall.

Grand County, CO (Zone 5a) Short season
114 days
Last Spring Frost May 28
114 growing days
First Fall Frost September 19

Grand County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (8 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 2
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Jul 23 – Sep 17
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Aug 13 – Oct 8

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 Grand County

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

Soil pH

Your soil pH (6.7–8.3) overlaps with Peas's range (6.0–7.5), though not a perfect match.

Soil Texture

The loam soil in Grand 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 (2.2%). 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.

Succession Planting Peas

2
successive plantings in your 114-day season

Sow every 6.3 weeks. Last sowing by Jul 11 to harvest before frost.

For a dedicated fall crop, sow by Jul 11.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 112 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 3" 3" 0" ✅ Rainfall sufficient
Jun 3" 1.5" 1.5" 🚿 Regular watering
Jul 3" 2" 1" 💧 Light watering
Aug 3" 2.3" 0.7" 💧 Light watering
Sep 3" 1.6" 1.4" 💧 Light watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Grand 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 ~719 GDD — county provides 1,311 GDD Excellent fit

Peas Planting Timeline — Grand County, CO

Peas Planting Calendar

Activity When Date Range
Start Indoors April 23 Apr 23 – May 7
Transplant Outdoors May 28 May 28 – Jun 11
Direct Sow May 14 May 14 – Jun 4
Harvest July 23 Jul 23 – Sep 17
Fall Sowing July 11 Jul 11 – Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

55–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

114 days in Grand County

Growing Tips for Peas in Grand County

Direct sow Peas outdoors after May 28 in Grand 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 Grand County, CO?

Grand County is in Zone 5a with an average last frost of May 28. Plan your Peas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grand County, CO?

Grand County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 28 and first fall frost is September 19.

🌱

Your Grand County Garden Planner — Free

A 24-page printable planner built for Grand 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 Grand County, CO. 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.