When to Plant Squash (Winter) in Clackamas County, OR
May in the garden — Clackamas County, Oregon
Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.
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Start squash (winter) indoors
Label every cell. You will absolutely forget which is which otherwise.
Winter squash includes butternut, acorn, delicata, and hubbard varieties grown to full maturity with hard rinds for storage. They develop sweet, dense flesh.
Clackamas County, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 28, giving you a growing season of approximately 197 days.
At an elevation of 199 feet, Clackamas County receives approximately 53.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Squash (Winter) during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Squash (Winter) root diseases.
Clackamas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.3
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 Clackamas County
How your county's soil matches Squash (Winter)'s growing requirements.
Soil pH
Your soil pH (5.7–6.3) overlaps with Squash (Winter)'s range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Clackamas County is excellent for Squash (Winter) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.7%) — Squash (Winter) will thrive.
How to Plant Squash (Winter)
Succession Planting Squash (Winter)
Sow every 9.1 weeks. Last sowing by Jun 30 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Squash (Winter)
Squash (Winter) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Squash (Winter) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 8.3" | 0" | ❄️ Dormant |
| Feb | — | 5.3" | 0" | ❄️ Dormant |
| Mar | — | 4.8" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4" | 0.3" | 💧 Light watering |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Jul | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Aug | 4.3" | 1" | 3.3" | 🚿 Regular watering |
| Sep | 4.3" | 2.2" | 2.1" | 💧 Light watering |
| Oct | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 8.2" | 0" | ❄️ Dormant |
| Dec | — | 8.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Clackamas County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Squash (Winter) 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.
Squash (Winter) Planting Timeline — Clackamas County, OR
Squash (Winter) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 17 | Mar 17 – Mar 31 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Direct Sow | April 14 | Apr 14 – May 5 |
| Harvest | July 14 | Jul 14 – Sep 8 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
80–120 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
197 days in Clackamas County
Growing Tips for Squash (Winter) in Clackamas County
Direct sow Squash (Winter) outdoors after April 14 in Clackamas County when soil has warmed and frost danger has passed.
Common pests for Squash (Winter) in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow after last frost on rich mounds. Allow ample space for sprawling vines. Cure harvested fruits in the sun for 10 days before storing in a cool, dry place.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Squash (Winter) in Other Locations
Frequently Asked Questions
When should I plant Squash (Winter) in Clackamas County, OR?
Clackamas County is in Zone 9a with an average last frost of April 14. Plan your Squash (Winter) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Clackamas County, OR?
Clackamas County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 14 and first fall frost is October 28.
Your Clackamas County Garden Planner — Free
A 24-page printable planner built for Clackamas 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.