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When to Plant Sunflower in Manitoba

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.

Manitoba spans USDA hardiness zones 3b, 4a, 4b (with planting data available), so planting dates vary by your location within the state. Click your zone below for the most accurate dates.

Find Your County

Click your county for exact Sunflower planting dates based on your local frost dates.

Sunflower Planting Calendar for Manitoba

Zone 3b ~135 day growing season · Full guide →

Last frost: May 10 · First frost: September 22 · 135 day season

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest August 9 Aug 9 – Sep 27
Zone 4a ~145 day growing season · Full guide →

Last frost: May 6 · First frost: September 28 · 145 day season

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest August 5 Aug 5 – Sep 23
Zone 4b ~155 day growing season · Full guide →

Last frost: May 1 · First frost: October 3 · 155 day season

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest July 31 Jul 31 – Sep 18

Growing Tips for Manitoba

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.

Frequently Asked Questions

When should I plant Sunflower in Manitoba?

Planting dates for Sunflower in Manitoba depend on your USDA zone. Manitoba spans zones 3b, 4a, 4b. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Manitoba for planting?

Manitoba contains USDA hardiness zones 3b, 4a, 4b. Your specific zone depends on your location within the state — northern and higher-elevation areas are in colder zones, while southern and coastal areas are warmer.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Last updated: April 2026.