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When to Plant Bachelor's Button in Minnesota

Bachelor's Button (Centaurea cyanus), also called cornflower, is a carefree cool-season annual best known for its vivid cobalt-blue flowers — one of the truest blues in the annual garden. It tolerates light frosts, self-seeds prolifically, and thrives in poor to average soils. A traditional cut flower and pollinator magnet, it has been cultivated in gardens for centuries.

Minnesota spans USDA hardiness zones 3b, 4a, 4b, 5a (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 Bachelor's Button planting dates based on your local frost dates.

Bachelor's Button Planting Calendar for Minnesota

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 15 Mar 15 – Mar 29
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Bloom July 12 Jul 12 – Sep 6
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 18 Mar 18 – Apr 1
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 22 Apr 22 – May 13
Bloom July 8 Jul 8 – Sep 9
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 March 13 Mar 13 – Mar 27
Transplant Outdoors May 1 May 1 – May 15
Direct Sow April 17 Apr 17 – May 8
Bloom July 3 Jul 3 – Sep 4
Zone 5a ~166 day growing season · Full guide →

Last frost: April 25 · First frost: October 8 · 166 day season

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 4 Apr 4 – Apr 25
Bloom June 27 Jun 27 – Sep 5

Growing Tips for Minnesota

Direct-sow in early spring as soon as soil can be worked; seeds need a brief cold period for best germination (refrigerate for a few days before planting if spring arrives quickly). In zones 6+, fall-sow for the earliest spring bloom. Thin to 12 inches; do not over-fertilize — too much nitrogen produces foliage at the expense of flowers. Deadhead to prolong blooming or allow self-seeding for a naturalized colony.

Frequently Asked Questions

When should I plant Bachelor's Button in Minnesota?

Planting dates for Bachelor's Button in Minnesota depend on your USDA zone. Minnesota spans zones 3b, 4a, 4b, 5a. Check the planting calendar above for your specific zone's frost dates and planting windows.

What zone is Minnesota for planting?

Minnesota contains USDA hardiness zones 3b, 4a, 4b, 5a. 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: June 2026.