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When to Plant Spinach in Eagle County, CO

Eagle County, Colorado Zone 5b May

This month in Eagle County, Colorado

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.

Avg. last frost June 16
Avg. first frost September 7
Soil temp (4") 36°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
June prep starts now
  • Transplants going out: spinach
  • Direct-sowing: spinach
  • Fall sowing: spinach

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Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Eagle County, Colorado is in USDA Zone 5b. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.

At an elevation of 7,116 feet, Eagle County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Spinach to ensure they mature before fall.

Eagle County, CO (Zone 5b) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7
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Eagle County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: May 1 Transplant: Jun 5 🍅 Harvest: Jul 10 – Sep 11
Recommended (50%) ✗ May not fit
Start indoors: May 12 Transplant: Jun 16 🍅 Harvest: Jul 21 – Sep 22
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: May 23 Transplant: Jun 27 🍅 Harvest: Aug 1 – Oct 3

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 Eagle County

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

Soil pH

Your soil pH (6.6–7.7) overlaps with Spinach's range (6.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Spinach.

How to Plant Spinach

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Spinach

2
successive plantings in your 83-day season

Sow every 4 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Jun 29.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Spinach

Spinach needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Spinach Needs Rainfall You Supplement Action
Jan 1.8" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 3.2" 0" ❄️ Dormant
Jun 3" 1.6" 1.4" 💧 Light watering
Jul 3" 2.1" 0.9" 💧 Light watering
Aug 3" 2.4" 0.6" 💧 Light watering
Sep 3" 1.8" 1.2" 💧 Light watering
Oct 2" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Spinach 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.

Spinach needs ~457 GDD — county provides 892 GDD Excellent fit

Spinach Planting Timeline — Eagle County, CO

Spinach Planting Calendar

Activity When Date Range
Start Indoors May 12 May 12 – May 26
Transplant Outdoors June 16 Jun 16 – Jun 30
Direct Sow June 2 Jun 2 – Jun 23
Harvest July 21 Jul 21 – Sep 22
Fall Sowing June 29 Jun 29 – Jul 13

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

83 days in Eagle County

Growing Tips for Spinach in Eagle County

Direct sow Spinach outdoors after June 16 in Eagle County when soil has warmed and frost danger has passed.

General growing tips

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Wind pollinated — isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Eagle County, CO?

Eagle County is in Zone 5b with an average last frost of June 16. Plan your Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Eagle County, CO?

Eagle County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 7.

🌱

Your Eagle County Garden Planner — Free

A 24-page printable planner built for Eagle County (Zone 5b). 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 Eagle 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.