When to Plant Leeks in Clatsop County, OR
Your May planting checklist for Clatsop County, Oregon
Each item below is timed to Clatsop County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Indoor seed-starting week for leeks
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
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.
Clatsop County, Oregon is in USDA Zone 9a. The average last spring frost is April 12 and the first fall frost is November 4, giving you a growing season of approximately 206 days.
At an elevation of 412 feet, Clatsop County receives approximately 54.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Leeks during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Leeks root diseases.
Clatsop County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.7
Drainage
Well Drained
Plant 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 Clatsop County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (5.6–6.7) overlaps with Leeks's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Clatsop County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.9%) — Leeks will thrive.
How to Plant Leeks
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Plant 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 | — | 8.4" | 0" | ❄️ Dormant |
| Feb | — | 5.2" | 0" | ❄️ Dormant |
| Mar | — | 4.8" | 0" | ❄️ Dormant |
| Apr | 3.5" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 3.5" | 3.6" | 0" | ✅ Rainfall sufficient |
| Jun | 3.5" | 2.1" | 1.4" | 💧 Light watering |
| Jul | 3.5" | 0.9" | 2.6" | 🚿 Regular watering |
| Aug | 3.5" | 1.1" | 2.4" | 🚿 Regular watering |
| Sep | 3.5" | 2.4" | 1.1" | 💧 Light watering |
| Oct | 3.5" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 3.5" | 8.4" | 0" | ✅ Rainfall sufficient |
| Dec | — | 9.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Nov in Clatsop 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 — Clatsop County, OR
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 15 | Mar 15 – Mar 29 |
| Transplant Outdoors | April 12 | Apr 12 – Apr 26 |
| Direct Sow | March 22 | Mar 22 – Apr 12 |
| Harvest | July 12 | Jul 12 – Sep 27 |
| Fall Sowing | September 9 | Sep 9 – Sep 23 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Fall Sowing Harvest |
| October | — |
| 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 9a
📆 Growing Season
206 days in Clatsop County
Growing Tips for Leeks in Clatsop County
Direct sow Leeks outdoors after April 12 in Clatsop 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
Frequently Asked Questions
When should I plant Leeks in Clatsop County, OR?
Clatsop County is in Zone 9a with an average last frost of April 12. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clatsop County, OR?
Clatsop County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 12 and first fall frost is November 4.
Your Clatsop County Garden Planner — Free
A 24-page printable planner built for Clatsop County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.