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When to Plant Cucumber in Pierce County, WA

Pierce County, Washington Zone 8b May

Your May gardening checklist

Welcome to May in Zone 8b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 13
Avg. first frost October 30
Soil temp (4") 70°F
Watering Moderate
Pest pressure High
Daylight 14.9 hrs
  1. Get cucumber seeds going inside

    You're about 25 weeks out from your last frost — the perfect window to get these germinating indoors.

Coming up in June — start thinking about
  • First harvests: cucumber

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Cucumbers are a warm-season vine crop available in slicing and pickling varieties. They are prolific producers when given warmth, moisture, and a trellis to climb.

Pierce County, Washington is in USDA Zone 8b. The average last spring frost is April 13 and the first fall frost is October 30, giving you a growing season of approximately 200 days.

At an elevation of 168 feet, Pierce County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Cucumber to ensure they mature before fall.

Pierce County, WA (Zone 8b) Long season
200 days
Last Spring Frost April 13
200 growing days
First Fall Frost October 30
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Pierce County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (66 days to spare)
Start indoors: Mar 7 Transplant: Apr 18 🍅 Harvest: Jun 13 – Aug 8
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jun 22 – Aug 17
Safe Start (90%) ✓ Fits season (66 days to spare)
Start indoors: Apr 18 Transplant: May 30 🍅 Harvest: Jul 25 – Sep 19

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 Pierce County

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

Soil pH

Your soil pH (5.4–6.2) is more acidic than Cucumber prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Cucumber will thrive.

How to Plant Cucumber

0.5"
Planting Depth
24"
Between Plants
48"
Between Rows

Succession Planting Cucumber

4
successive plantings in your 200-day season

Sow every 5.7 weeks. Last sowing by Aug 21 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 842 gal / 100 sq ft

Monthly Watering Guide for Cucumber

Cucumber needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Cucumber Needs Rainfall You Supplement Action
Jan 6.8" 0" ❄️ Dormant
Feb 5.7" 0" ❄️ Dormant
Mar 4.4" 0" ❄️ Dormant
Apr 6.5" 4.1" 2.4" 💧 Light watering
May 6.5" 2.8" 3.7" 🚿 Regular watering
Jun 6.5" 2" 4.5" 🚿 Regular watering
Jul 6.5" 0.9" 5.6" 🚿 Regular watering
Aug 6.5" 0.9" 5.6" 🚿 Regular watering
Sep 6.5" 2" 4.5" 🚿 Regular watering
Oct 6.5" 4.7" 1.8" 💧 Light watering
Nov 7.8" 0" ❄️ Dormant
Dec 6.8" 0" ❄️ Dormant

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

Cucumber 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.

Cucumber needs ~735 GDD — county provides 2,450 GDD Excellent fit

Cucumber Planting Timeline — Pierce County, WA

Cucumber Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors April 27 Apr 27 – May 11
Direct Sow April 20 Apr 20 – May 11
Harvest June 22 Jun 22 – Aug 17

Plant 0.5" deep · 24" apart · Rows 48" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
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

1.5"/week · 1-2 times/week

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

200 days in Pierce County

Growing Tips for Cucumber in Pierce County

Direct sow Cucumber outdoors after April 13 in Pierce County when soil has warmed and frost danger has passed.

Common pests for Cucumber 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 or start indoors 3 weeks early. Provide a trellis for vining types to save space and improve air circulation. Harvest frequently to encourage production.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cucumber in Pierce County, WA?

Pierce County is in Zone 8b with an average last frost of April 13. Plan your Cucumber planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pierce County, WA?

Pierce County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is April 13 and first fall frost is October 30.

🌱

Your Pierce County Garden Planner — Free

A 24-page printable planner built for Pierce County (Zone 8b). 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 Pierce 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.