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When to Plant Soybeans in Garfield County, CO

Garfield County, Colorado Zone 6a May

May in the garden — Garfield County, Colorado

Each item below is timed to Garfield County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 25
Avg. first frost September 21
Soil temp (4") 35°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
June prep starts now
  • Direct-sowing: soybeans

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Soybeans (edamame) are a high-protein legume that fixes nitrogen in the soil. Fresh green soybeans harvested at the edamame stage are a nutritious snack.

Garfield County, Colorado is in USDA Zone 6a. The average last spring frost is May 25 and the first fall frost is September 21, giving you a growing season of approximately 119 days.

At an elevation of 7,997 feet, Garfield County receives approximately 21.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Soybeans to ensure they mature before fall.

Garfield County, CO (Zone 6a) Short season
119 days
Last Spring Frost May 25
119 growing days
First Fall Frost September 21
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Garfield County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 14 🍅 Harvest: Aug 6 – Oct 1
Recommended (50%) ✗ May not fit
Transplant: May 25 🍅 Harvest: Aug 17 – Oct 12
Safe Start (90%) ✗ May not fit
Transplant: Jun 14 🍅 Harvest: Sep 6 – Nov 1

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 Garfield County

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

Soil pH

Your soil pH (6.5–7.9) is more alkaline than Soybeans prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Soybeans.

How to Plant Soybeans

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 315 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Soybeans

Soybeans needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Soybeans Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.8" 2.5" 🚿 Regular watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

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

Soybeans 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.

Soybeans needs ~1,300 GDD — county provides 1,547 GDD Good fit

Soybeans Planting Timeline — Garfield County, CO

Soybeans Planting Calendar

Activity When Date Range
Direct Sow June 1 Jun 1 – Jun 22
Harvest August 24 Aug 24 – Oct 19

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

119 days in Garfield County

Growing Tips for Soybeans in Garfield County

Direct sow Soybeans outdoors after May 25 in Garfield County when soil has warmed and frost danger has passed.

Your 119.0-day growing season in Garfield County is tight for Soybeans (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

Garfield County receives only 21" of rain annually. Soybeans needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil warms to 60F. Plant in blocks rather than rows for better pollination. Harvest for edamame when pods are plump and bright green.

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 Soybeans in Garfield County, CO?

Garfield County is in Zone 6a with an average last frost of May 25. Plan your Soybeans planting based on this frost date — see the calendar above for exact timing.

What planting zone is Garfield County, CO?

Garfield County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 25 and first fall frost is September 21.

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Your Garfield County Garden Planner — Free

A 24-page printable planner built for Garfield County (Zone 6a). 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 Garfield 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.