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When to Plant Leeks in Cowley County, KS

Cowley County, Kansas Zone 7a May

This month in Cowley County, Kansas

May is a pivotal month for Cowley County, Kansas gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 11
Avg. first frost October 25
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14 hrs
  1. Begin indoor sowing: leeks

    Label every cell. You will absolutely forget which is which otherwise.

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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.

Cowley County, Kansas is in USDA Zone 7a. The average last spring frost is April 11 and the first fall frost is October 25, giving you a growing season of approximately 197 days.

At an elevation of 708 feet, Cowley County receives approximately 31.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Leeks during the growing season.

Cowley County, KS (Zone 7a) Moderate season
197 days
Last Spring Frost April 11
197 growing days
First Fall Frost October 25

Cowley County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Feb 27 Transplant: Apr 3 🍅 Harvest: Jul 3 – Sep 18
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jul 11 – Sep 26
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jul 23 – Oct 8

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 Cowley County

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

Soil pH

Your soil pH (6.4–7.3) overlaps with Leeks's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Leeks will thrive.

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.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.7″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 214 gal / 100 sq ft

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 0.8" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.5" 3.3" 0.2" 💧 Light watering
May 3.5" 4.7" 0" ✅ Rainfall sufficient
Jun 3.5" 5.3" 0" ✅ Rainfall sufficient
Jul 3.5" 4" 0" ✅ Rainfall sufficient
Aug 3.5" 3.5" 0" ✅ Rainfall sufficient
Sep 3.5" 2.7" 0.8" 💧 Light watering
Oct 3.5" 2.2" 1.3" 💧 Light watering
Nov 1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cowley 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 ~1,830 GDD — county provides 3,004 GDD Excellent fit

Leeks Planting Timeline — Cowley County, KS

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow March 28 Mar 28 – Apr 18
Harvest July 11 Jul 11 – Sep 26
Fall Sowing August 16 Aug 16 – Aug 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Only during dry spells

📅 Days to Maturity

90–150 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

197 days in Cowley County

Growing Tips for Leeks in Cowley County

Direct sow Leeks outdoors after April 11 in Cowley County when soil has warmed and frost danger has passed.

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 Cowley County, KS?

Cowley County is in Zone 7a with an average last frost of April 11. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cowley County, KS?

Cowley County, Kansas is in USDA Hardiness Zone 7a. The average last spring frost is April 11 and first fall frost is October 25.

🌱

Your Cowley County Garden Planner — Free

A 24-page printable planner built for Cowley County (Zone 7a). 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 Cowley County, KS. Local conditions may vary. Last updated: May 2026.

Sources & credits

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