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When to Plant Chayote in Washington County, OR

Washington County, Oregon Zone 8b May

Your May game plan for Washington County, Oregon

Here's what deserves your attention in Washington County, Oregon this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost April 15
Avg. first frost October 27
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
June prep starts now
  • Starting indoors: chayote

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Chayote is a tropical vine producing pear-shaped, mild-flavored squash. The entire plant is edible including the fruit, shoots, leaves, and tuberous root.

Washington County, Oregon is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 27, giving you a growing season of approximately 195 days.

At an elevation of 352 feet, Washington County receives approximately 47.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Chayote during the growing season.

Washington County, OR (Zone 8b) Moderate season
195 days
Last Spring Frost April 15
195 growing days
First Fall Frost October 27

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 18 Transplant: Apr 22 🍅 Harvest: Aug 26 – Nov 4
Recommended (50%) ✗ May not fit
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Sep 2 – Nov 11
Safe Start (90%) ✗ May not fit
Start indoors: Mar 20 Transplant: May 22 🍅 Harvest: Sep 25 – Dec 4

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 Washington County

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

Soil pH

Your soil pH (5.8–6.4) overlaps with Chayote's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.7%) — Chayote will thrive.

How to Plant Chayote

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Chayote

Chayote needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Chayote Needs Rainfall You Supplement Action
Jan 7.4" 0" ❄️ Dormant
Feb 5.7" 0" ❄️ Dormant
Mar 4.2" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 0.6" 3.7" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 7.3" 0" ❄️ Dormant
Dec 8" 0" ❄️ Dormant

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

Chayote 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.

Chayote needs ~2,062 GDD — county provides 2,681 GDD Excellent fit

Chayote Planting Timeline — Washington County, OR

Chayote Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 22 Apr 22 – May 13
Harvest September 2 Sep 2 – Nov 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

195 days in Washington County

Growing Tips for Chayote in Washington County

Direct sow Chayote outdoors after April 15 in Washington County when soil has warmed and frost danger has passed.

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

General growing tips

Plant the whole fruit at a 45-degree angle with the stem end exposed. Provide a very sturdy trellis. One vine can produce 60-80 fruits. Harvest when fruits are young and tender.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Chayote in Washington County, OR?

Washington County is in Zone 8b with an average last frost of April 15. Plan your Chayote planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, OR?

Washington County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 15 and first fall frost is October 27.

🌱

Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington 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 Washington 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.