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When to Plant Acorn Squash in Lewis County, WA

Lewis County, Washington Zone 8a May

Your May planting checklist for Lewis County, Washington

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

Avg. last frost April 25
Avg. first frost October 24
Soil temp (4") 66°F
Watering High
Pest pressure Moderate
Daylight 14.8 hrs
  1. Harden off and plant acorn squash

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Sow acorn squash where they'll grow

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

  3. Start acorn squash indoors

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

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Acorn squash is a small winter squash with dark green, ribbed skin and mildly sweet orange flesh. It is perfect for stuffing and roasting as individual servings.

Lewis County, Washington is in USDA Zone 8a. The average last spring frost is April 25 and the first fall frost is October 24, giving you a growing season of approximately 182 days.

At an elevation of 327 feet, Lewis County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Acorn Squash during the growing season.

Lewis County, WA (Zone 8a) Moderate season
182 days
Last Spring Frost April 25
182 growing days
First Fall Frost October 24

Lewis County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Mar 16 Transplant: Apr 27 🍅 Harvest: Jul 20 – Aug 24
Recommended (50%) ✓ Fits season (49 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Aug 1 – Sep 5
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: May 27 Transplant: Jul 8 🍅 Harvest: Sep 30 – Nov 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 Lewis County

How your county's soil matches Acorn Squash's growing requirements.

Soil pH

Your soil pH (5.6–6.2) is within Acorn Squash's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.3%) — Acorn Squash will thrive.

How to Plant Acorn Squash

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

Succession Planting Acorn Squash

2
successive plantings in your 182-day season

Sow every 9.1 weeks. Last sowing by Jul 16 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 388 gal / 100 sq ft

Monthly Watering Guide for Acorn Squash

Acorn Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Acorn Squash Needs Rainfall You Supplement Action
Jan 5.6" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 4.8" 2.8" 2" 💧 Light watering
May 4.8" 2" 2.8" 🚿 Regular watering
Jun 4.8" 1.3" 3.5" 🚿 Regular watering
Jul 4.8" 0.6" 4.2" 🚿 Regular watering
Aug 4.8" 0.6" 4.2" 🚿 Regular watering
Sep 4.8" 1.4" 3.4" 🚿 Regular watering
Oct 4.8" 3.4" 1.4" 💧 Light watering
Nov 6.3" 0" ❄️ Dormant
Dec 5.7" 0" ❄️ Dormant

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

Acorn Squash 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.

Acorn Squash needs ~1,305 GDD — county provides 2,639 GDD Excellent fit

Acorn Squash Planting Timeline — Lewis County, WA

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest August 1 Aug 1 – Sep 5

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 8a

📆 Growing Season

182 days in Lewis County

Growing Tips for Acorn Squash in Lewis County

Direct sow Acorn Squash outdoors after April 25 in Lewis County when soil has warmed and frost danger has passed.

Common pests for Acorn Squash 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. Harvest when the ground spot turns orange and the skin is hard. Acorn squash has a shorter storage life than butternut, lasting about 2 months.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Acorn Squash in Lewis County, WA?

Lewis County is in Zone 8a with an average last frost of April 25. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis County, WA?

Lewis County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 25 and first fall frost is October 24.

🌱

Your Lewis County Garden Planner — Free

A 24-page printable planner built for Lewis County (Zone 8a). 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 Lewis 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.