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When to Plant Leeks in Coffey County, KS

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.

Coffey County, Kansas is in USDA Zone 6a. The average last spring frost is April 11 and the first fall frost is October 24, giving you a growing season of approximately 196 days.

At an elevation of 466 feet, Coffey County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Leeks during the growing season.

Coffey County, KS (Zone 6a) Moderate season
196 days
Last Spring Frost April 11
196 growing days
First Fall Frost October 24

Coffey County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: Jul 5 – Sep 20
Recommended (50%) ✓ Fits season (28 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 18 Transplant: Apr 22 🍅 Harvest: Jul 22 – Oct 7

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 Coffey County

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

Soil pH

Your soil pH (6.5โ€“7.7) is more alkaline than Leeks prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Coffey County is excellent for Leeks โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). 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.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 432 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” 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 โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 0.9" 0" โ„๏ธ Dormant
Mar โ€” 1.7" 0" โ„๏ธ Dormant
Apr 3.5" 3.1" 0.4" ๐Ÿ’ง Light watering
May 3.5" 4.1" 0" โœ… Rainfall sufficient
Jun 3.5" 3.9" 0" โœ… Rainfall sufficient
Jul 3.5" 3.4" 0.1" ๐Ÿ’ง Light watering
Aug 3.5" 3.5" 0" โœ… Rainfall sufficient
Sep 3.5" 2.9" 0.6" ๐Ÿ’ง Light watering
Oct 3.5" 1.6" 1.9" ๐Ÿšฟ Regular watering
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Coffey County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 2,989 GDD Excellent fit

Leeks Planting Timeline โ€” Coffey County, KS

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 โ€“ Mar 21
Transplant Outdoors April 11 Apr 11 โ€“ Apr 25
Direct Sow March 28 Mar 28 โ€“ Apr 18
Harvest July 11 Jul 11 โ€“ Sep 26
Fall Sowing August 15 Aug 15 โ€“ Aug 29

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.8"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

90โ€“150 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

196 days in Coffey County

Growing Tips for Leeks in Coffey County

Direct sow Leeks outdoors after April 11 in Coffey 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 Coffey County, KS?

Coffey County is in Zone 6a with an average last frost of April 11. Plan your Leeks planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Coffey County, KS?

Coffey County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 11 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Coffey County gardeners in Zone 6a 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 Coffey County, KS. Local conditions may vary. Last updated: April 2026.