When to Plant Sunflowers in Alberta – 2026
Published: April 27, 2026
Alberta spans Canadian hardiness zones across multiple cities. Plant sunflowers in Alberta from june 1 through 15 (after last frost — calgary june 7, edmonton june 2).. Victoria Day weekend is the standard sunflower direct-sowing date in southern Ontario and Quebec. Sowing earlier risks rot in cold wet soil; sowing later compresses the bloom window before late September frost.
Sunflowers Planting Window for Alberta
Direct sow sunflower seeds after last frost when soil reaches 10°C / 50°F. Most zones: April–June. Warm-season annual — does not tolerate frost. Days to bloom: 70–100 days from seed.
For Alberta specifically, the recommended planting window is June 1 through 15 (after last frost — Calgary June 7, Edmonton June 2).. Alberta gardens across multiple climate zones — adjust based on your specific city. Victoria Day weekend is the standard sunflower direct-sowing date in southern Ontario and Quebec. Sowing earlier risks rot in cold wet soil; sowing later compresses the bloom window before late September frost.
Sunflowers are tender annuals — frost kills them at any age. Direct sow only after last frost when soil reaches 10°C.
Alberta Cities — Sunflowers Planting Dates
Each city below has local frost dates, Canadian zone, and a city-specific sunflowers planting calendar.
Best Sunflowers Varieties for Alberta
For Alberta , choose varieties rated for your zone or one zone colder for reliable winter survival. The Canadian-bred or tested varieties below perform well in Alberta conditions.
Tall (3 m) classic giant sunflower. 90 days to bloom — works in southern Ontario and BC; tight for Calgary/Edmonton.
Branching habit, 1.5 m tall, multiple golden-yellow blooms. 60 days. Excellent for short-season Prairies.
Cut-flower industry standard. 50-60 days. Successive sowings every 2 weeks for continuous Canadian blooms.
Branching pale yellow. 1.5-2 m tall. 90 days. Excellent for pollinators in Ontario and Quebec gardens.
60 cm container-friendly fully-double yellow blooms. 60 days. Works on Prairie balconies.
Caring for Sunflowers in Alberta
Sow method: direct sow after last frost. The steps below adapt the general planting advice for Alberta's climate and timing.
- →Direct sow sunflower seeds 2.5 cm (1 inch) deep, after the last frost when soil reaches 10°C (50°F).
- →Space giant varieties 60 cm (24 inches) apart; branching types 30 cm (12 inches); dwarf 20 cm (8 inches).
- →Choose a site with full sun (8+ hours) — sunflowers track the sun and lean toward shade.
- →Water consistently for the first 3 weeks; once established, water deeply weekly during dry periods.
- →Stake giant varieties at planting — adding stakes after the plant reaches 1 m (3 ft) damages roots.
- →Sidedress with balanced fertilizer when plants reach 60 cm (2 ft) tall — once is enough.
Frequently Asked Questions about Sunflowers in Alberta
When should I plant sunflowers in Alberta?
Plant sunflowers in Alberta from june 1 through 15 (after last frost — calgary june 7, edmonton june 2).. Direct sow sunflower seeds after last frost when soil reaches 10°C / 50°F. Most zones: April–June. Warm-season annual — does not tolerate frost. Days to bloom: 70–100 days from seed.
What Canadian zones are in Alberta?
Alberta spans multiple Canadian hardiness zones depending on location. Major cities and their zones: Calgary (Zone 4a), Edmonton (Zone 4a), Red Deer (Zone 3b). Check planthardiness.gc.ca for your exact postal code.
What sunflowers varieties grow best in Alberta?
Mongolian Giant (Mammoth) (All Canadian zones): Tall (3 m) classic giant sunflower. 90 days to bloom — works in southern Ontario and BC; tight for Calgary/Edmonton. Soraya (All Canadian zones): Branching habit, 1.5 m tall, multiple golden-yellow blooms. 60 days. Excellent for short-season Prairies.