When to Plant Leeks in Covington, OH
What to do in June
Here's what deserves your attention in Covington, OH this month. Everything below is tailored to Zone 6a and timed around your local frost dates.
July will be here before you know it — start on
- First harvests: 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.
Covington, Ohio is in USDA Zone 6a. The average last spring frost is April 25 and the first fall frost is October 17, giving you a growing season of approximately 175 days.
At an elevation of 973 feet, Miami County receives approximately 40.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Covington Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.3
Drainage
Well Drained
Leeks Planting Risk Windows
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 Covington
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (5.9–7.3) overlaps with Leeks's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Miami County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.0%) — Leeks will thrive.
How to Plant Leeks
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Leeks Water Budget
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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.9" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 3.5" | 4.1" | 0" | ✅ Rainfall sufficient |
| May | 3.5" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 4.9" | 0" | ✅ Rainfall sufficient |
| Jul | 3.5" | 5.1" | 0" | ✅ Rainfall sufficient |
| Aug | 3.5" | 4.3" | 0" | ✅ Rainfall sufficient |
| Sep | 3.5" | 3.4" | 0.1" | 💧 Light watering |
| Oct | 3.5" | 3.5" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Miami 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 Planting Timeline — Covington, OH
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 21 | Mar 21 – Apr 4 |
| Transplant Outdoors | April 25 | Apr 25 – May 9 |
| Direct Sow | April 11 | Apr 11 – May 2 |
| Harvest | July 25 | Jul 25 – Oct 10 |
| Fall Sowing | August 8 | Aug 8 – Aug 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 · Natural rainfall sufficient
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
175 days in Miami County
Growing Tips for Leeks in Covington
Direct sow Leeks outdoors after April 25 in Miami 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
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
Your Miami County Garden Planner — Free
A 22-page printable planner built for Miami County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.