Coreopsis, commonly known as Tickseed, is a cheerful and resilient plant often grown as an annual or perennial. This member of the Asteraceae family is valued for its long blooming season and tendency to readily self-seed. Saving seeds is a simple process that allows for propagation and expanding color in the landscape the following season. This guide outlines the steps necessary to successfully collect, cure, and store Coreopsis seeds for future planting.
Identifying the Optimal Time for Harvest
The window for collecting viable Coreopsis seeds begins after the petals have fallen and the plant shifts its energy from flowering to seed development. To allow the flower heads to mature fully, you must stop deadheading, which encourages more blooms. The visual cue that signals ripeness is the transformation of the remaining green central disk into a dry, brown, and brittle seed head.
This change typically occurs in late summer or early fall. Coreopsis often produces flowers and seeds simultaneously, meaning harvest can be staggered throughout the season. The seed head must be fully dried on the stem and still intact, as an overly-mature head will crack open and spill its tiny, dark seeds onto the ground. The ideal time is just when the flower head has turned completely brown and feels crisp to the touch, but before the seeds have begun to naturally disperse.
Step-by-Step Seed Collection
Harvesting Coreopsis seeds is straightforward, requiring only a pair of small, sharp snips or scissors and a paper bag. Select seed heads that are completely dry and brown, ensuring they are still tightly closed to confirm the seeds are contained inside. Cut the stem a few inches below the dried seed head, placing the entire severed portion directly into the paper bag.
Collecting the entire seed head minimizes the chance of losing the minute seeds. Alternatively, if the seed head is loose but not yet open, gently cup your hand underneath and lightly flick the stem to encourage the dark, tick-like seeds to fall into your palm or a container. The paper bag method is preferred for larger quantities, as the harvested material can continue to dry within the bag away from the elements.
Curing, Storage, and Next Steps
Once the seed heads are removed from the plant, they require a thorough drying or “curing” period before being processed and stored. Spread the collected seed heads thinly on a screen or newspaper in a cool, dry location with good air circulation for one to two weeks. This step reduces the moisture content to below ten percent, which prevents mold and rot during long-term storage.
After curing, the seeds must be separated from the surrounding plant material, known as chaff. Gently crush the dried seed heads between your fingers, releasing the small, brown to maroon-colored seeds from their capsules. The resulting mixture of seeds and chaff can be cleaned by a process called winnowing. This involves carefully pouring the mixture from one container to another in front of a fan, allowing the lighter chaff to blow away.
Store the fully cleaned and dried seeds in a small, airtight container, such as a glass jar or a sealed paper envelope, labeled with the species and date of collection. The best location for storage is a cool, dark, and consistently dry environment to maximize viability, which can last for two to three years. Many Coreopsis species benefit from a period of cold, moist stratification for 30 to 60 days to break dormancy before planting indoors in late winter, while others can be direct-sown outdoors in the fall.