Blog

When to Plant Microgreens in Routt County, CO

Routt County, Colorado Zone 5a May

What to do in May

Your Routt County, Colorado garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost June 12
Avg. first frost September 8
Soil temp (4") 39°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Seed microgreens outdoors

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

June prep starts now
  • Transplants going out: microgreens
  • First harvests: microgreens
  • Fall sowing: microgreens

Instant PDF download. No spam, unsubscribe any time.

Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Routt County, Colorado is in USDA Zone 5a. The average last spring frost is June 12 and the first fall frost is September 8, giving you a growing season of approximately 88 days.

At an elevation of 5,381 feet, Routt County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Microgreens to ensure they mature before fall.

Routt County, CO (Zone 5a) Very short season
88 days
Last Spring Frost June 12
88 growing days
First Fall Frost September 8

Routt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Apr 28 Transplant: Jun 2 🍅 Harvest: Jun 9 – Jul 7
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: May 8 Transplant: Jun 12 🍅 Harvest: Jun 19 – Jul 17
Safe Start (90%) ✓ Fits season (55 days to spare)
Start indoors: May 21 Transplant: Jun 25 🍅 Harvest: Jul 2 – Jul 30

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 Routt County

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

Soil pH

Your soil pH (6.7–7.9) is more alkaline than Microgreens prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

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

Succession Planting Microgreens

17
successive plantings in your 88-day season

Sow every 0.7 weeks. Last sowing by Aug 18 to harvest before frost.

For a dedicated fall crop, sow by Jun 30.

Plant Water Budget

Plant needs
1.0″/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 Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 2.8" 0" ❄️ Dormant
Jun 4.3" 1.5" 2.8" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 2.3" 2" 💧 Light watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

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

Microgreens 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.

Microgreens needs ~172 GDD — county provides 1,078 GDD Excellent fit

Microgreens Planting Timeline — Routt County, CO

Microgreens Planting Calendar

Activity When Date Range
Start Indoors May 8 May 8 – May 22
Transplant Outdoors June 12 Jun 12 – Jun 26
Direct Sow May 29 May 29 – Jun 19
Harvest June 19 Jun 19 – Jul 17
Fall Sowing June 30 Jun 30 – Jul 14

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

7–21 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

88 days in Routt County

Growing Tips for Microgreens in Routt County

Direct sow Microgreens outdoors after June 12 in Routt County when soil has warmed and frost danger has passed.

Your generous 88.0-day season in Routt County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

Routt County receives only 24" of rain annually. Microgreens needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Routt County, CO?

Routt County is in Zone 5a with an average last frost of June 12. Plan your Microgreens planting based on this frost date — see the calendar above for exact timing.

What planting zone is Routt County, CO?

Routt County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 12 and first fall frost is September 8.

🌱

Your Routt County Garden Planner — Free

A 24-page printable planner built for Routt 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 Routt 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.