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When to Plant Squash (Winter) in Edmonton, AB

Winter squash includes butternut, acorn, delicata, and hubbard varieties grown to full maturity with hard rinds for storage. They develop sweet, dense flesh.

Edmonton, Alberta is in USDA Zone 4b. The average last spring frost is May 13 and the first fall frost is October 7, giving you a growing season of approximately 147 days.

At an elevation of 2,191 feet, Edmonton receives approximately 17.4 inches of rainfall annually with predominantly dark brown chernozem soil. Summer highs average 70°F, so choose short-season varieties of Squash (Winter) to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Squash (Winter) successfully. Mulch heavily to conserve soil moisture.

Edmonton, AB (Zone 4b) Short season
147 days
Last Spring Frost May 13
147 growing days
First Fall Frost October 7

Edmonton Soil Profile

Soil Type

Dark Brown Chernozem

Soil pH

6.0-7.0

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 29 – Sep 23
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 29 – Sep 23
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 29 – Sep 23

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.

How to Plant Squash (Winter)

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 658 gal / 100 sq ft

Monthly Watering Guide for Squash (Winter)

Squash (Winter) 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 (Winter) Needs Rainfall You Supplement Action
Jan 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 4.3" 1.9" 2.4" 🚿 Regular watering
Jun 4.3" 2.1" 2.2" 🚿 Regular watering
Jul 4.3" 2" 2.3" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.3" 3" 🚿 Regular watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Squash (Winter) 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.

Squash (Winter) needs ~250 GDD — county provides 367 GDD Excellent fit

Squash (Winter) Planting Timeline — Edmonton, AB

Squash (Winter) Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors June 3 Jun 3 – Jun 17
Direct Sow May 27 May 27 – Jun 17
Harvest August 26 Aug 26 – Oct 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 4b

📆 Growing Season

147 days in Edmonton

Growing Tips for Squash (Winter) in Edmonton

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

Edmonton receives only 17" of rain annually. Squash (Winter) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost on rich mounds. Allow ample space for sprawling vines. Cure harvested fruits in the sun for 10 days before storing in a cool, dry place.

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 (Winter) in Edmonton, AB?

Edmonton is in Zone 4b with an average last frost of May 13. Plan your Squash (Winter) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Edmonton, AB?

Edmonton, Alberta is in USDA Hardiness Zone 4b. The average last spring frost is May 13 and first fall frost is October 7.

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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 Edmonton, AB. 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.