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When to Plant Acorn Squash in Powell County, MT

Powell County, Montana Zone 4b May

May in the garden — Powell County, Montana

We've pulled the most time-sensitive tasks for Powell County, Montana this May and put them front and centre. Tackle them in order.

Avg. last frost June 6
Avg. first frost September 8
Soil temp (4") 40°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
Before June arrives, get these ready
  • 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.

Powell County, Montana is in USDA Zone 4b. The average last spring frost is June 6 and the first fall frost is September 8, giving you a growing season of approximately 94 days.

At an elevation of 5,514 feet, Powell County receives approximately 22.9 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Acorn Squash to ensure they mature before fall.

Powell County, MT (Zone 4b) Very short season
94 days
Last Spring Frost June 6
94 growing days
First Fall Frost September 8

Powell County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 8 Transplant: Jun 10 🍅 Harvest: Sep 2 – Oct 7
Recommended (50%) ✗ May not fit
Start indoors: Apr 25 Transplant: Jun 27 🍅 Harvest: Sep 19 – Oct 24
Safe Start (90%) ✗ May not fit
Start indoors: May 9 Transplant: Jul 11 🍅 Harvest: Oct 3 – Nov 7

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 Powell County

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

Soil pH

Your soil pH (6.5–8.2) 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 Powell 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
0.1″/week
Watering frequency Only during dry spells
Season total 77 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 1.6" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 3" 0" ❄️ Dormant
Jun 4.8" 1.4" 3.4" 🚿 Regular watering
Jul 4.8" 2.1" 2.7" 🚿 Regular watering
Aug 4.8" 2.2" 2.6" 🚿 Regular watering
Sep 4.8" 1.8" 3" 🚿 Regular watering
Oct 2.1" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Powell 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 ~1,170 GDD — county provides 1,222 GDD Good fit

Acorn Squash Planting Timeline — Powell County, MT

Acorn Squash Planting Calendar

Activity When Date Range
Start Indoors April 25 Apr 25 – May 9
Transplant Outdoors June 27 Jun 27 – Jul 11
Direct Sow June 20 Jun 20 – Jul 11
Harvest September 19 Sep 19 – Oct 24

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 4b

📆 Growing Season

94 days in Powell County

Growing Tips for Acorn Squash in Powell County

Direct sow Acorn Squash outdoors after June 06 in Powell County when soil has warmed and frost danger has passed.

Your 94.0-day growing season in Powell 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.

Powell County receives only 23" 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 Powell County, MT?

Powell County is in Zone 4b with an average last frost of June 6. Plan your Acorn Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Powell County, MT?

Powell County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is June 6 and first fall frost is September 8.

🌱

Your Powell County Garden Planner — Free

A 24-page printable planner built for Powell County (Zone 4b). 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 Powell County, MT. 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.