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When to Plant Leeks in Cambridge, OH

Leeks
Guernsey County, Ohio Zone 6b June

June in the garden — Guernsey County, Ohio

Your garden in Guernsey County, Ohio is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 30
Avg. first frost October 16
Soil temp (4") 75°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Fire up the seed-starting tray: leeks

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Get ahead of July
  • 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.

Cambridge, Ohio is in USDA Zone 6b. The average last spring frost is April 30 and the first fall frost is October 16, giving you a growing season of approximately 169 days.

At an elevation of 790 feet, Guernsey County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Leeks during the growing season.

Cambridge, OH (Zone 6b) Moderate season
169 days
Last Spring Frost April 30
169 growing days
First Fall Frost October 16

Cambridge Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Leeks Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 23 Transplant: Apr 27 🍅 Harvest: Jul 27 – Oct 12
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 30 – Oct 15
Safe Start (90%) ✗ May not fit
Start indoors: Apr 12 Transplant: May 17 🍅 Harvest: Aug 16 – Nov 1

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 Cambridge

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

Soil pH

Your soil pH (6.0–7.0) is within Leeks's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — 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.

Leeks Water Budget

Plant needs
0.8″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 74 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 1.2" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.5" 2.8" 0.7" 💧 Light watering
May 3.5" 3.4" 0.1" 💧 Light watering
Jun 3.5" 4.1" 0" ✅ Rainfall sufficient
Jul 3.5" 3.6" 0" ✅ Rainfall sufficient
Aug 3.5" 3.1" 0.4" 💧 Light watering
Sep 3.5" 2.5" 1" 💧 Light watering
Oct 3.5" 2.4" 1.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Guernsey 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 ~2,190 GDD — county provides 3,084 GDD Excellent fit

Leeks Planting Timeline — Cambridge, OH

Leeks Planting Calendar

Activity When Date Range
Start Indoors March 26 Mar 26 – Apr 9
Transplant Outdoors April 30 Apr 30 – May 14
Direct Sow April 16 Apr 16 – May 7
Harvest July 30 Jul 30 – Oct 15
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6b

📆 Growing Season

169 days in Guernsey County

Growing Tips for Leeks in Cambridge

Direct sow Leeks outdoors after April 30 in Guernsey 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 →

🌱

Your Guernsey County Garden Planner — Free

A 22-page printable planner built for Guernsey County (Zone 6b). 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 Guernsey County, OH. Local conditions may vary. Last updated: June 2026.