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When to Plant Leeks in Ouray 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.

Ouray County, Colorado is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 10, giving you a growing season of approximately 84 days.

At an elevation of 7,449 feet, Ouray County receives approximately 12.6 inches of rainfall annually with predominantly loam soil. Summer highs average 86ยฐF, providing good warmth for Leeks during the growing season. With low rainfall, drip irrigation is essential for growing Leeks successfully. Mulch heavily to conserve soil moisture.

Ouray County, CO (Zone 5a) Very short season
84 days
Last Spring Frost June 18
84 growing days
First Fall Frost September 10

Ouray County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Aug 12 – Oct 28
Recommended (50%) ✗ May not fit
Start indoors: May 14 Transplant: Jun 18 🍅 Harvest: Sep 17 – Dec 3
Safe Start (90%) ✗ May not fit
Start indoors: May 25 Transplant: Jun 29 🍅 Harvest: Sep 28 – Dec 14

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
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 332 gal / 100 sq ft
Drought risk

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

Leeks needs ~1,740 GDD — county provides 1,218 GDD May not mature

Leeks Planting Timeline โ€” Ouray County, CO

Leeks Planting Calendar

Activity When Date Range
Start Indoors May 14 May 14 โ€“ May 28
Transplant Outdoors June 18 Jun 18 โ€“ Jul 2
Direct Sow June 4 Jun 4 โ€“ Jun 25
Fall Sowing July 2 Jul 2 โ€“ Jul 16
Harvest September 17 Sep 17 โ€“ Dec 3

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

Month-by-Month Timeline

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

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

84 days

Growing Tips for Ouray 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 Ouray County, CO?

Ouray County is in Zone 5a with an average last frost of June 18. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ouray County, CO?

Ouray County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 10.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ouray County gardeners in Zone 5a 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 Ouray County, CO. Local conditions may vary. Last updated: April 2026.