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When to Plant Sunflower in Fort McMurray, AB

Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Fort McMurray, Alberta is in USDA Zone 3b. The average last spring frost is May 27 and the first fall frost is October 1, giving you a growing season of approximately 127 days.

At an elevation of 1,213 feet, Fort McMurray receives approximately 18.1 inches of rainfall annually with predominantly dark brown chernozem soil. Summer highs average 64°F, so choose short-season varieties of Sunflower to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Sunflower successfully. Mulch heavily to conserve soil moisture.

Fort McMurray, AB (Zone 3b) Short season
127 days
Last Spring Frost May 27
127 growing days
First Fall Frost October 1

Fort McMurray 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 (43 days to spare)
Start indoors: Feb 11 Transplant: May 6 🍅 Harvest: Jul 15 – Sep 2
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Feb 11 Transplant: May 6 🍅 Harvest: Jul 15 – Sep 2
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Feb 11 Transplant: May 6 🍅 Harvest: Jul 15 – Sep 2

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 Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 2" 0.2" 💧 Light watering
Jul 2.2" 1.9" 0.3" 💧 Light watering
Aug 2.2" 1.8" 0.4" 💧 Light watering
Sep 2.2" 1.8" 0.4" 💧 Light watering
Oct 2.2" 1.6" 0.6" 💧 Light watering
Nov 1.2" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Sunflower 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.

Sunflower needs ~0 GDD — county provides 0 GDD May not mature

Sunflower Planting Timeline — Fort McMurray, AB

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors June 17 Jun 17 – Jul 1
Direct Sow June 10 Jun 10 – Jul 1
Harvest August 26 Aug 26 – Oct 14

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 3b

📆 Growing Season

127 days in Fort McMurray

Growing Tips for Sunflower in Fort McMurray

Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Fort McMurray receives only 18" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Fort McMurray, AB?

Fort McMurray is in Zone 3b with an average last frost of May 27. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fort McMurray, AB?

Fort McMurray, Alberta is in USDA Hardiness Zone 3b. The average last spring frost is May 27 and first fall frost is October 1.

🌱

Your Fort McMurray Garden Planner — Free

A 24-page printable planner built for Fort McMurray (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Fort McMurray, 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.