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When to Plant Acorn Squash in Clark County, ID

Clark County, Idaho Zone 5b May

May in Clark County, Idaho — your action list

Here's what deserves your attention in Clark County, Idaho this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost June 7
Avg. first frost September 10
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: acorn squash
  • Direct-sowing: acorn squash

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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.

Clark County, Idaho is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 10, giving you a growing season of approximately 95 days.

At an elevation of 7,493 feet, Clark County receives approximately 21.9 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Clark County, ID (Zone 5b) Very short season
95 days
Last Spring Frost June 7
95 growing days
First Fall Frost September 10
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Clark County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 18 Transplant: Jun 6 🍅 Harvest: Aug 29 – Oct 3
Recommended (50%) ✗ May not fit
Start indoors: May 3 Transplant: Jun 21 🍅 Harvest: Sep 13 – Oct 18
Safe Start (90%) ✗ May not fit
Start indoors: May 17 Transplant: Jul 5 🍅 Harvest: Sep 27 – Nov 1

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 Clark County

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

Soil pH

Your soil pH (6.8–7.8) is more alkaline than Acorn Squash prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Acorn Squash.

How to Plant Acorn Squash

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

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 134 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 2.5" 0" ❄️ Dormant
Jun 4.8" 1.5" 3.3" 🚿 Regular watering
Jul 4.8" 1.7" 3.1" 🚿 Regular watering
Aug 4.8" 2.2" 2.6" 🚿 Regular watering
Sep 4.8" 1.7" 3.1" 🚿 Regular watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Clark 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 ~1,035 GDD — county provides 1,092 GDD Good fit

Acorn Squash Planting Timeline — Clark County, ID

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors May 3 May 3 – May 17
Transplant Outdoors June 21 Jun 21 – Jul 5
Direct Sow June 14 Jun 14 – Jul 5
Harvest September 13 Sep 13 – Oct 18

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5b

📆 Growing Season

95 days in Clark County

Growing Tips for Acorn Squash in Clark County

Direct sow Acorn Squash outdoors after June 07 in Clark County when soil has warmed and frost danger has passed.

Your 95.0-day growing season in Clark County is tight for Acorn Squash (80.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Clark County receives only 22" of rain annually. Acorn Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Clark County, ID?

Clark County is in Zone 5b with an average last frost of June 7. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clark County, ID?

Clark County, Idaho is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 10.

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Your Clark County Garden Planner — Free

A 24-page printable planner built for Clark County (Zone 5b). 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 Clark County, ID. 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.