Agrostemma (Corn Cockle) in Zone 6a & 6b
Agrostemma githago
When to plant agrostemma (corn cockle) in zone 6b
Zones 6a and 6b 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. Agrostemma (Corn Cockle) tolerates either.
| Start indoors | Mar 28–Apr 4 |
|---|---|
| Direct sow / transplant outside | Apr 11–Apr 18 |
| Estimated bloom | Jun 25–Jul 2 (~75 days after planting) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.

Agrostemma, better known as corn cockle, has a history as an unwanted weed in European grain fields before it found a second life as a deliberately grown cut flower. Its delicate, magenta-pink blooms on tall, wiry stems have the airy, cottage-garden look that's hard to get from a sturdier, more structured flower.
How agrostemma (corn cockle) fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Agrostemma (Corn Cockle) needs about 75 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Agrostemma (Corn Cockle).
Where to buy agrostemma seeds
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See it growing
Search YouTube for "growing agrostemma (corn cockle)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 6b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Agrostemma (Corn Cockle) in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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