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When to Plant Zucchini in Stevens County, WA

Stevens County, Washington Zone 6b May

Your May planting checklist for Stevens County, Washington

Your Stevens County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 10
Avg. first frost September 24
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 15 hrs
  1. Plant out zucchini

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

  2. Sow zucchini where they'll grow

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June will be here before you know it — start on
  • Starting indoors: zucchini

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Stevens County, Washington is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is September 24, giving you a growing season of approximately 137 days.

At an elevation of 1,751 feet, Stevens County receives approximately 24.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Zucchini to ensure they mature before fall.

Stevens County, WA (Zone 6b) Short season
137 days
Last Spring Frost May 10
137 growing days
First Fall Frost September 24

Stevens County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Jul 4 – Aug 29
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Jul 12 – Sep 6
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 24 Transplant: Jun 12 🍅 Harvest: Jul 31 – Sep 25

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 Stevens County

How your county's soil matches Zucchini's growing requirements.

Soil pH

Your soil pH (5.3–6.3) is more acidic than Zucchini prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Stevens County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.3%) — Zucchini will thrive.

How to Plant Zucchini

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

Succession Planting Zucchini

3
successive plantings in your 137-day season

Sow every 5.1 weeks. Last sowing by Jul 26 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.8″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 551 gal / 100 sq ft

Monthly Watering Guide for Zucchini

Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Zucchini Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 5.2" 1.3" 3.9" 🚿 Regular watering
Jun 5.2" 0.9" 4.3" 🚿 Regular watering
Jul 5.2" 0.3" 4.9" 🚿 Regular watering
Aug 5.2" 0.4" 4.8" 🚿 Regular watering
Sep 5.2" 0.9" 4.3" 🚿 Regular watering
Oct 2.3" 0" ❄️ Dormant
Nov 4.2" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Stevens County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Zucchini 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.

Zucchini needs ~643 GDD — county provides 1,678 GDD Excellent fit

Zucchini Planting Timeline — Stevens County, WA

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest July 12 Jul 12 – Sep 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · 1-2 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Stevens County

Growing Tips for Zucchini in Stevens County

Direct sow Zucchini outdoors after May 10 in Stevens County when soil has warmed and frost danger has passed.

Common pests for Zucchini in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

Stevens County receives only 24" of rain annually. Zucchini needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Recommended Zucchini Varieties for Stevens County

Quick-producing varieties for shorter seasons

Black Beauty (50d) Raven (48d) Eight Ball (40d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Stevens County, WA?

Stevens County is in Zone 6b with an average last frost of May 10. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Stevens County, WA?

Stevens County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is September 24.

🌱

Your Stevens County Garden Planner — Free

A 24-page printable planner built for Stevens County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Stevens 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.