When to Plant Sunflowers in Fredericton, NB – 2026
Published: April 27, 2026
Fredericton is in Canadian Zone 5b (St. John River valley continental maritime). Last spring frost averages May 10; first fall frost October 8; the growing season runs about 151 frost-free days. Plant sunflowers in Fredericton from late may through early june..
Sunflowers Planting Window for Fredericton, NB
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 Fredericton, NB specifically, the recommended planting window is Late May through early June.. Fredericton's St. John River valley creates a warmer microclimate than surrounding uplands. The city has New Brunswick's most productive growing conditions for warm-season crops. Long daylight hours in June-July produce exceptional tomato and pepper quality.
Sunflowers are tender annuals — frost kills them at any age. Direct sow only after last frost when soil reaches 10°C.
Best Sunflowers Varieties for Fredericton, NB
For Fredericton, NB (Canadian Zone 5b), choose varieties rated for your zone or one zone colder for reliable winter survival. The Canadian-bred or tested varieties below perform well in New Brunswick 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.
How to Plant Sunflowers in Fredericton
Sow method: direct sow after last frost. The steps below adapt the general planting advice for Fredericton, NB'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 Fredericton, NB
When can I plant sunflowers in Fredericton?
Plant sunflowers in Fredericton from late may through early june. based on the city's Canadian Zone 5b. Last spring frost: May 10; first fall frost: October 8; frost-free growing season: 151 days.
What Canadian zone is Fredericton?
Fredericton is in Canadian Zone 5b (USDA equivalent 5a). The climate is st. john river valley continental maritime. Fredericton's St. John River valley creates a warmer microclimate than surrounding uplands. The city has New Brunswick's most productive growing conditions for warm-season crops. Long daylight hours in June-July produce exceptional tomato and pepper quality.
Are sunflowers winter-hardy in Fredericton?
Sunflowers are tender annuals — frost kills them at any age. Direct sow only after last frost when soil reaches 10°C.