Plains Coreopsis (Coreopsis tinctoria)

Difficulty: ⭐☆☆☆☆

(Very easy — heavy seed producer, minimal processing required)

Seed Collection Time:

Late summer through early fall — typically August to September, after flowering ends.

Signs Seeds are Ready:

• After blooming, the flower heads dry to brown and papery.

• Disk florets fall away, leaving behind the dark, narrow seeds (achenes).

• Seeds are firm, dark brown to black, and detach easily when rubbed.

• Mature seeds rattle or shake free from the dried heads.

Seed Collection Steps:

1. Clip entire dried flower heads once they are brown and brittle.

2. Place heads in a paper bag and allow them to finish drying for about a week.

3. Rub heads gently between your fingers to release seeds.

4. Clean seeds by removing papery chaff with a fine screen or winnowing.

Germination Tips:

• No stratification is required — seeds germinate readily.

• Sow in spring directly outdoors or indoors 6–8 weeks before the last frost.

• Lightly press seeds into soil surface — they need light for germination.

G: Sow fresh or store dry until spring. Seeds usually germinate in 1–3 weeks under warm, moist conditions.