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

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

Kittitas County, Washington is in USDA Zone 6a. The average last spring frost is May 7 and the first fall frost is October 2, giving you a growing season of approximately 148 days.

At an elevation of 2,468 feet, Kittitas County receives approximately 18.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, 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.

Kittitas County, WA (Zone 6a) Short season
148 days
Last Spring Frost May 7
148 growing days
First Fall Frost October 2

Kittitas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 26 Transplant: May 14 🍅 Harvest: Jul 2 – Sep 3
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Apr 2 Transplant: May 21 🍅 Harvest: Jul 9 – Sep 10
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Apr 19 Transplant: Jun 7 🍅 Harvest: Jul 26 – Sep 27

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 Kittitas County

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

Soil pH

Your soil pH (5.5โ€“6.7) overlaps with Squash (Summer)'s range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Kittitas County is excellent for Squash (Summer) โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) โ€” Squash (Summer) will thrive.

How to Plant Squash (Summer)

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

Succession Planting Squash (Summer)

3
successive plantings in your 148-day season

Sow every 5.1 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 733 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Squash (Summer) needs ~962 GDD — county provides 2,590 GDD Excellent fit

Squash (Summer) Planting Timeline โ€” Kittitas County, WA

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 โ€“ Apr 16
Transplant Outdoors May 21 May 21 โ€“ Jun 4
Direct Sow May 14 May 14 โ€“ Jun 4
Harvest July 9 Jul 9 โ€“ Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

45โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

148 days in Kittitas County

Growing Tips for Squash (Summer) in Kittitas County

Direct sow Squash (Summer) outdoors after May 07 in Kittitas County when soil has warmed and frost danger has passed.

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.

Kittitas County receives only 19" of rain annually. Squash (Summer) needs consistent moisture โ€” 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

Level Up Your Garden

Frequently Asked Questions

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

Kittitas County is in Zone 6a with an average last frost of May 7. Plan your Squash (Summer) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Kittitas County, WA?

Kittitas County, Washington is in USDA Hardiness Zone 6a. The average last spring frost is May 7 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Kittitas County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Kittitas County, WA. Local conditions may vary. Last updated: April 2026.