Blog

When to Plant Leeks in Morgan County, CO

Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.

Morgan County, Colorado is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 7,673 feet, Morgan County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Leeks to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Leeks successfully. Mulch heavily to conserve soil moisture.

Morgan County, CO (Zone 5a) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Morgan County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Aug 1 – Oct 17
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 10 🍅 Harvest: Aug 9 – Oct 25
Safe Start (90%) ✗ May not fit
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Aug 19 – Nov 4

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
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 782 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Leeks needs ~1,560 GDD — county provides 1,924 GDD Good fit

Leeks Planting Timeline โ€” Morgan County, CO

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 โ€“ Apr 19
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow April 26 Apr 26 โ€“ May 17
Fall Sowing July 27 Jul 27 โ€“ Aug 10
Harvest August 9 Aug 9 โ€“ Oct 25

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“150 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

148 days

Growing Tips for Morgan County

Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Level Up Your Garden

Frequently Asked Questions

When should I plant Leeks in Morgan County, CO?

Morgan County is in Zone 5a with an average last frost of May 10. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Morgan County, CO?

Morgan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 5.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Morgan County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Morgan County, CO. Local conditions may vary. Last updated: April 2026.