Blog

When to Plant Squash (Summer) in Glacier County, MT

Summer squash includes zucchini, yellow crookneck, and pattypan varieties that are harvested young and tender. They are prolific producers in warm weather.

Glacier County, Montana is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 18, giving you a growing season of approximately 119 days.

At an elevation of 8,147 feet, Glacier County receives approximately 13.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Squash (Summer) to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Squash (Summer) successfully. Mulch heavily to conserve soil moisture.

Glacier County, MT (Zone 4a) Short season
119 days
Last Spring Frost May 22
119 growing days
First Fall Frost September 18

Glacier County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Jul 24 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Apr 10 Transplant: Jun 12 🍅 Harvest: Jul 31 – Oct 2
Safe Start (90%) ✗ May not fit
Start indoors: Apr 30 Transplant: Jul 2 🍅 Harvest: Aug 20 – Oct 22

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 Glacier County

How your county's soil matches Squash (Summer)'s growing requirements.

Soil pH

Your soil pH (6.3โ€“8.1) overlaps with Squash (Summer)'s range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The loam soil in Glacier County is excellent for Squash (Summer) โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Squash (Summer)

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

Succession Planting Squash (Summer)

3
successive plantings in your 119-day season

Sow every 5.1 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 674 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Squash (Summer)

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

Month Squash (Summer) Needs Rainfall You Supplement Action
Jan โ€” 0.8" 0" โ„๏ธ Dormant
Feb โ€” 0.8" 0" โ„๏ธ Dormant
Mar โ€” 1" 0" โ„๏ธ Dormant
Apr โ€” 1.3" 0" โ„๏ธ Dormant
May 4.3" 1.6" 2.7" ๐Ÿšฟ Regular watering
Jun 4.3" 1" 3.3" ๐Ÿšฟ Regular watering
Jul 4.3" 1.3" 3" ๐Ÿšฟ Regular watering
Aug 4.3" 1.4" 2.9" ๐Ÿšฟ Regular watering
Sep 4.3" 1.1" 3.2" ๐Ÿšฟ Regular watering
Oct โ€” 1.3" 0" โ„๏ธ Dormant
Nov โ€” 1" 0" โ„๏ธ Dormant
Dec โ€” 0.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Glacier County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Squash (Summer) 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" โ€” every day above 50ยฐF 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.

Squash (Summer) needs ~550 GDD — county provides 1,190 GDD Excellent fit

Squash (Summer) Planting Timeline โ€” Glacier County, MT

Squash (Summer) Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 โ€“ Apr 24
Transplant Outdoors June 12 Jun 12 โ€“ Jun 26
Direct Sow June 5 Jun 5 โ€“ Jun 26
Harvest July 31 Jul 31 โ€“ Oct 2

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

45โ€“65 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

119 days in Glacier County

Growing Tips for Squash (Summer) in Glacier County

Direct sow Squash (Summer) outdoors after May 22 in Glacier County when soil has warmed and frost danger has passed.

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

Glacier County receives only 13" of rain annually. Squash (Summer) needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost on mounds. Harvest frequently when fruits are 6-8 inches for best texture. Check plants daily as they grow rapidly in summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Squash (Summer) in Glacier County, MT?

Glacier County is in Zone 4a with an average last frost of May 22. Plan your Squash (Summer) planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Glacier County, MT?

Glacier County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 18.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Glacier County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Glacier County, MT. Local conditions may vary. Last updated: April 2026.