Blog

When to plant Leeks in Routt County, CO

Plant Leeks in Routt County from May 29 to June 19 in spring. Routt County sits in USDA Zone 5a, with last frost around June 12 and first frost on September 8. A second sowing from June 30 to July 14 extends the harvest into fall.

When to Plant Leeks in Routt County, CO

Leeks

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.

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 Leeks 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

Monthly Watering Guide for Leeks

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

Month Leeks 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.

Leeks Planting Timeline — Routt County, CO

Leeks 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 September 11 Sep 11 – Nov 27
Fall Sowing June 30 Jun 30 – Jul 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5a

📆 Growing Season

88 days in Routt County

Growing Tips for Routt 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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Leeks in Routt County, CO?

Routt County is in Zone 5a with an average last frost of June 12. Plan your Leeks 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.

When should I plant Leeks in Routt County, CO?

In Routt County, CO, plant Leeks after the last frost (around June 12) and before the first frost (around September 8). Best results when soil holds above 50°F.

What growing zone is Routt County, CO for Leeks?

Routt County sits in USDA Zone 5a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.

Can Leeks grow in Routt County's climate?

Yes — Leeks grows well in Routt County's temperate climate. Routt County averages a 88-day frost-free season, with last frost around June 12 and first frost around September 8.

🌱

Your Routt County Garden Planner — Free

A 22-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: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.