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When to Plant Onion in Manitoba

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

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 Onion planting dates based on your local frost dates.

Onion Planting Calendar for Manitoba

โ–ธ Zone 3b ~135 day growing season ยท Full guide โ†’

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

Activity When Date Range
Start Indoors March 29 Mar 29 โ€“ Apr 12
Transplant Outdoors May 10 May 10 โ€“ May 24
Direct Sow May 3 May 3 โ€“ May 24
Harvest August 9 Aug 9 โ€“ Sep 13
Fall Sowing June 30 Jun 30 โ€“ Jul 14
โ–ธ Zone 4a ~145 day growing season ยท Full guide โ†’

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

Activity When Date Range
Start Indoors March 25 Mar 25 โ€“ Apr 8
Transplant Outdoors May 6 May 6 โ€“ May 20
Direct Sow April 29 Apr 29 โ€“ May 20
Harvest August 5 Aug 5 โ€“ Sep 23
Fall Sowing July 6 Jul 6 โ€“ Jul 20
โ–ธ Zone 4b ~155 day growing season ยท Full guide โ†’

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

Activity When Date Range
Start Indoors March 20 Mar 20 โ€“ Apr 3
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 24 Apr 24 โ€“ May 15
Harvest July 31 Jul 31 โ€“ Sep 18
Fall Sowing July 11 Jul 11 โ€“ Jul 25

Growing Tips for Manitoba

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Frequently Asked Questions

When should I plant Onion in Manitoba?

Planting dates for Onion 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 โ€” 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.