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When to Plant Squash (Summer) in Chelan County, WA

Chelan County, Washington Zone 7a May

May in Chelan County, Washington — your action list

We've pulled the most time-sensitive tasks for Chelan County, Washington this May and put them front and centre. Tackle them in order.

Avg. last frost April 24
Avg. first frost October 20
Soil temp (4") 54°F
Watering Critical
Pest pressure Low
Daylight 14.9 hrs
  1. Move squash (summer) into the garden

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow squash (summer) where they'll grow

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

  3. Begin indoor sowing: squash (summer)

    Your window is short. These crops want several weeks of indoor growth before they go outside.

A few tasks this May that'll pay off in June
  • First harvests: squash (summer)

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Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Chelan County, Washington is in USDA Zone 7a. The average last spring frost is April 24 and the first fall frost is October 20, giving you a growing season of approximately 179 days.

At an elevation of 3,517 feet, Chelan County receives approximately 14.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Squash (Summer) during the growing season. With low rainfall, drip irrigation is essential for growing Squash (Summer) successfully. Mulch heavily to conserve soil moisture.

Chelan County, WA (Zone 7a) Moderate season
179 days
Last Spring Frost April 24
179 growing days
First Fall Frost October 20
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Chelan County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jun 15 – Aug 17
Recommended (50%) ✓ Fits season (53 days to spare)
Start indoors: Mar 27 Transplant: May 8 🍅 Harvest: Jun 26 – Aug 28
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Jul 21 – Sep 22

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 Chelan County

How your county's soil matches Squash (Summer)'s growing requirements.

Soil pH

Your soil pH (5.5–6.3) is more acidic than Squash (Summer) prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Chelan County is excellent for Squash (Summer) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.1%) — Squash (Summer) will thrive.

How to Plant Squash (Summer)

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Squash (Summer)

4
successive plantings in your 179-day season

Sow every 5.1 weeks. Last sowing by Aug 16 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 1,275 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 2.1" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 4.3" 1.2" 3.1" 🚿 Regular watering
May 4.3" 0.9" 3.4" 🚿 Regular watering
Jun 4.3" 0.6" 3.7" 🚿 Regular watering
Jul 4.3" 0.2" 4.1" 🚿 Regular watering
Aug 4.3" 0.3" 4" 🚿 Regular watering
Sep 4.3" 0.5" 3.8" 🚿 Regular watering
Oct 4.3" 1.2" 3.1" 🚿 Regular watering
Nov 1.9" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Chelan 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) needs ~839 GDD — county provides 2,729 GDD Excellent fit

Squash (Summer) Planting Timeline — Chelan County, WA

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors March 27 Mar 27 – Apr 10
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest June 26 Jun 26 – Aug 28

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

45–65 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 7a

📆 Growing Season

179 days in Chelan County

Growing Tips for Squash (Summer) in Chelan County

Direct sow Squash (Summer) outdoors after April 24 in Chelan County when soil has warmed and frost danger has passed.

Your generous 179.0-day season in Chelan 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.

Chelan County receives only 14" of rain annually. Squash (Summer) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Summer) in Chelan County, WA?

Chelan County is in Zone 7a with an average last frost of April 24. Plan your Squash (Summer) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Chelan County, WA?

Chelan County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 24 and first fall frost is October 20.

🌱

Your Chelan County Garden Planner — Free

A 24-page printable planner built for Chelan County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Chelan County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.