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When to plant Leeks in Lincoln County, CO

Lincoln County's climate puts the Leeks spring window between April 29 and May 20. time plantings around the expected last-frost window for best survival. A second sowing from July 25 to August 8 extends the harvest into fall.

When to Plant Leeks in Lincoln County, CO

Leeks
Lincoln County, Colorado Zone 5b July

What to do in July

Your garden in Lincoln County, Colorado is working on a schedule, even when you're not. Here's where you should be this July.

Avg. last frost May 13
Avg. first frost October 3
Soil temp (4") 60°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Start your fall crops: leeks

    Mid-season soil is hot. Sow a bit deeper than the packet suggests to find cooler, damper ground.

Looking ahead to August
  • First harvests: leeks

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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.

Lincoln County, Colorado is in USDA Zone 5b. The average last spring frost is May 13 and the first fall frost is October 3, giving you a growing season of approximately 143 days.

At an elevation of 6,293 feet, Lincoln County receives approximately 13.9 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, 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.

Lincoln County, CO (Zone 5b) Short season
143 days
Last Spring Frost May 13
143 growing days
First Fall Frost October 3

Lincoln County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Aug 8 – Oct 24
Recommended (50%) ✗ May not fit
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Aug 12 – Oct 28
Safe Start (90%) ✗ May not fit
Start indoors: Apr 25 Transplant: May 30 🍅 Harvest: Aug 29 – Nov 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.

Soil Compatibility in Lincoln County

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

Soil pH

Your soil pH (6.6–8.3) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Leeks.

How to Plant Leeks

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
0.4″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 598 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Leeks

Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Leeks Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 3.5" 1.4" 2.1" 🚿 Regular watering
Jun 3.5" 0.9" 2.6" 🚿 Regular watering
Jul 3.5" 1.3" 2.2" 🚿 Regular watering
Aug 3.5" 1.7" 1.8" 🚿 Regular watering
Sep 3.5" 1.1" 2.4" 🚿 Regular watering
Oct 3.5" 1.2" 2.3" 🚿 Regular watering
Nov 1" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Leeks 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.

Leeks needs ~1,740 GDD — county provides 2,073 GDD Good fit

Leeks Planting Timeline — Lincoln County, CO

Leeks Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 13 May 13 – May 27
Direct Sow April 29 Apr 29 – May 20
Harvest August 12 Aug 12 – Oct 28
Fall Sowing July 25 Jul 25 – Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

143 days in Lincoln County

Growing Tips for Leeks in Lincoln County

Direct sow Leeks outdoors after May 13 in Lincoln County when soil has warmed and frost danger has passed.

Your 143.0-day growing season in Lincoln County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Lincoln County, CO?

Lincoln County is in Zone 5b with an average last frost of May 13. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lincoln County, CO?

Lincoln County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 13 and first fall frost is October 3.

When should I plant Leeks in Lincoln County, CO?

In Lincoln County, CO, plant Leeks after the last frost (around May 13) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Lincoln County, CO for Leeks?

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

Can Leeks grow in Lincoln County's climate?

Yes — Leeks grows well in Lincoln County's temperate climate. Lincoln County averages a 143-day frost-free season, with last frost around May 13 and first frost around October 3.

🌱

Your Lincoln County Garden Planner — Free

A 22-page printable planner built for Lincoln County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Lincoln County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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