When to Plant Squash (Summer) in Island County, WA
Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.
Island County, Washington is in USDA Zone 8a. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.
At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Squash (Summer) during the growing season.
Island 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 Island County
How your county's soil matches Squash (Summer)'s growing requirements.
Soil pH
Your soil pH (5.6–6.7) overlaps with Squash (Summer)'s range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Island County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.3%) — Squash (Summer) will thrive.
How to Plant Squash (Summer)
Succession Planting Squash (Summer)
Sow every 5.1 weeks. Last sowing by Aug 30 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Squash (Summer)
Squash (Summer) 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 (Summer) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.8" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Nov | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 7.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Island County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Squash (Summer) 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 (Summer) Planting Timeline — Island County, WA
Squash (Summer) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 1 | Jun 1 – Aug 3 |
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 | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
45–65 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 8a
📆 Growing Season
218 days in Island County
Growing Tips for Squash (Summer) in Island County
Direct sow Squash (Summer) outdoors after March 30 in Island County when soil has warmed and frost danger has passed.
Your generous 218.0-day season in Island County allows multiple plantings of Squash (Summer). Sow every 22.0 days for continuous harvest.
Common pests for Squash (Summer) 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 mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Squash (Summer) in Other Locations
Frequently Asked Questions
When should I plant Squash (Summer) in Island County, WA?
Island County is in Zone 8a with an average last frost of March 30. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Island County, WA?
Island County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is March 30 and first fall frost is November 3.
Plan Your Garden with Confidence
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