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When to Plant Zucchini in Wallowa County, OR

Wallowa County, Oregon Zone 6b May

Wallowa County, Oregon gardeners: here's your May plan

May is a pivotal month for Wallowa County, Oregon gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 11
Avg. first frost September 22
Soil temp (4") 57°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
  1. Set out zucchini seedlings

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  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.

Before June arrives, get these ready
  • 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.

Wallowa County, Oregon is in USDA Zone 6b. The average last spring frost is May 11 and the first fall frost is September 22, giving you a growing season of approximately 134 days.

At an elevation of 1,240 feet, Wallowa County receives approximately 22.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Zucchini during the growing season.

Wallowa County, OR (Zone 6b) Short season
134 days
Last Spring Frost May 11
134 growing days
First Fall Frost September 22

Wallowa County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Mar 27 Transplant: May 15 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Apr 6 Transplant: May 25 🍅 Harvest: Jul 13 – Sep 7
Safe Start (90%) ✓ Fits season (20 days to spare)
Start indoors: May 8 Transplant: Jun 26 🍅 Harvest: Aug 14 – Oct 9

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 Wallowa County

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

Soil pH

Your soil pH (5.3–6.2) is more acidic than Zucchini prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is excellent (5.4%) — Zucchini will thrive.

How to Plant Zucchini

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

Succession Planting Zucchini

3
successive plantings in your 134-day season

Sow every 5.1 weeks. Last sowing by Jul 24 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.7″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,016 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 2.9" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 5.2" 1.3" 3.9" 🚿 Regular watering
Jun 5.2" 1" 4.2" 🚿 Regular watering
Jul 5.2" 0.4" 4.8" 🚿 Regular watering
Aug 5.2" 0.4" 4.8" 🚿 Regular watering
Sep 5.2" 1" 4.2" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 3.9" 0" ❄️ Dormant
Dec 3.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Wallowa 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 ~722 GDD — county provides 1,842 GDD Excellent fit

Zucchini Planting Timeline — Wallowa County, OR

Zucchini Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 18 May 18 – Jun 8
Harvest July 13 Jul 13 – Sep 7

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 · 2-3 times/week

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

134 days in Wallowa County

Growing Tips for Zucchini in Wallowa County

Direct sow Zucchini outdoors after May 11 in Wallowa 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.

Wallowa County receives only 23" 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 Wallowa 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 Wallowa County, OR?

Wallowa County is in Zone 6b with an average last frost of May 11. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wallowa County, OR?

Wallowa County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 11 and first fall frost is September 22.

🌱

Your Wallowa County Garden Planner — Free

A 24-page printable planner built for Wallowa 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.

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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 Wallowa County, OR. 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.