Agrostemma (Corn Cockle) in Zone 4a & 4b

Agrostemma githago

When to plant agrostemma (corn cockle) in zone 4b

Zones 4a and 4b 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 indoorsApr 17–Apr 24
Direct sow / transplant outsideMay 1–May 8
Estimated bloomJul 15–Jul 22 (~75 days after planting)

Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 2-3 ft.

Agrostemma (Corn Cockle)
Photo: Antti Bilund via Wikimedia Commons, CC BY-SA 3.0, cropped.

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 4's season

Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. 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)

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Growing Agrostemma (Corn Cockle) in USDA zone 4b

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Growing Agrostemma (Corn Cockle) in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.

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