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When to Plant Microgreens in Delta County, CO

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.

Delta County, Colorado is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 8, giving you a growing season of approximately 160 days.

At an elevation of 4,470 feet, Delta County receives approximately 13.4 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Microgreens during the growing season. With low rainfall, drip irrigation is essential for growing Microgreens successfully. Mulch heavily to conserve soil moisture.

Delta County, CO (Zone 6a) Moderate season
160 days
Last Spring Frost May 1
160 growing days
First Fall Frost October 8

Delta County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (130 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🍅 Harvest: Apr 29 – May 27
Recommended (50%) ✓ Fits season (125 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: May 8 – Jun 5
Safe Start (90%) ✓ Fits season (126 days to spare)
Start indoors: Apr 12 Transplant: May 17 🍅 Harvest: May 24 – Jun 21

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,108 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Microgreens needs ~214 GDD — county provides 2,440 GDD Excellent fit

Microgreens Planting Timeline โ€” Delta County, CO

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 โ€“ Apr 10
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 17 Apr 17 โ€“ May 8
Fall Sowing July 30 Jul 30 โ€“ Aug 13
Harvest May 8 May 8 โ€“ Jun 5

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

7โ€“21 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6a

Growing Season

160 days

Growing Tips for Delta County

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 Delta County, CO?

Delta County is in Zone 6a with an average last frost of May 1. Plan your Microgreens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delta County, CO?

Delta County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 8.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delta County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Delta County, CO. Local conditions may vary. Last updated: April 2026.