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When to Plant Sunflower in Dauphin, MB

Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.

Dauphin, Manitoba is in USDA Zone 4a. The average last spring frost is May 17 and the first fall frost is October 4, giving you a growing season of approximately 140 days.

At an elevation of 1,000 feet, Dauphin receives approximately 12 inches of rainfall annually with predominantly black chernozem soil. Summer highs average 74°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.

Annual Blooms in Summer Pollinator-friendly Good for cutting
Dauphin, MB (Zone 4a) Short season
140 days
Last Spring Frost May 17
140 growing days
First Fall Frost October 4

Dauphin Soil Profile

Soil Type

Black Chernozem

Soil pH

6.0-7.0

Drainage

Well Drained

Sunflower Planting Timeline — Dauphin, MB

Sunflower Planting Calendar

Activity When Date Range
Start Indoors April 26 Apr 26 – May 10
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 31 May 31 – Jun 21
Bloom August 23 Aug 23 – Oct 18

Plant 1" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: N/A

🗺️ USDA Zone

Zone 4a

📆 Growing Season

140 days in Dauphin

Growing Tips for Dauphin

Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes
  • Pole_beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Dauphin, MB?

Dauphin is in Zone 4a with an average last frost of May 17. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dauphin, MB?

Dauphin, Manitoba is in USDA Hardiness Zone 4a. The average last spring frost is May 17 and first fall frost is October 4.

🌱

Your Dauphin Garden Planner — Free

A 22-page printable planner built for Dauphin (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Dauphin, MB. Local conditions may vary. Last updated: June 2026.

Sources & credits

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