Bachelor's Button (Cornflower) in Zone 3a & 3b
Centaurea cyanus
When to plant bachelor's button (cornflower) in zone 3b
Zones 3a and 3b share the same average frost dates in our data, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Bachelor's Button (Cornflower) tolerates either.
| Start indoors | Apr 11–Apr 18 |
|---|---|
| Direct sow / transplant outside | May 16–May 23 |
| Estimated bloom | Jul 30–Aug 6 (~75 days after planting) |
Spacing: 3 per square foot (square-foot-gardening spacing). Mature height: 1-3 ft.

Bachelor's button (also sold as cornflower) is about as low-effort as annual flowers get. It tolerates cold better than most, fills in fast, and doesn't ask for much once it's in the ground. Wiry 1- to 3-foot stems carry small, fringed, frilly round blooms, most often blue, though pink, white, and maroon show up in mixes too.
How bachelor's button (cornflower) fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Bachelor's Button (Cornflower) needs about 75 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Bachelor's Button (Cornflower).
Where to buy bachelor's button seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing bachelor's button (cornflower)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Bachelor's Button (Cornflower) in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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