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Cup Plant Seeds:
Guide to Storing, Sowing and Germination

Updated: March 24, 2022

Cup plants (Silphium perfoliatum) are tall, leafy plants that produce bright yellow flowers in the summer. They are known for their unique cup-shaped leaves that hold water, providing a valuable resource for birds and insects. The seeds of the cup plant can be harvested and planted to grow new plants. Here is a guide to storing, sowing, and germinating cup plant seeds.

Storing Cup Plant Seeds

Cup plant seeds can be collected from mature plants in the fall after the flowers have faded and the seed heads have turned brown. The seeds should be fully mature before harvesting to ensure the best chances of successful germination.

Once you have collected the seeds, it is important to store them properly to maintain their viability. Cup plant seeds can be stored in a cool, dry place for up to two years. Keep them in an airtight container such as a jar or plastic bag to prevent moisture from getting in.

Sowing Cup Plant Seeds

Cup plant seeds can be sown directly into the ground in the fall or early spring. Choose a location with full sun and well-drained soil. Sow the seeds about 1/4 inch deep and cover with soil. Water the area lightly to help settle the soil around the seeds.

If you prefer to start your cup plant seeds indoors, you can do so about six weeks before your last frost date. Fill small pots with potting soil and sow one seed per pot. Keep the soil moist but not waterlogged, and place the pots in a warm, sunny location.

Germinating Cup Plant Seeds

Cup plant seeds typically take between 10-14 days to germinate. Keep the soil moist during this time but avoid overwatering as this can cause damping off disease.

Once the seedlings have emerged, they will need to be thinned to allow space for growth. Choose the strongest seedling in each pot and remove the others. If you have sown your seeds directly into the ground, thin them to about 18-24 inches apart.

Cup plants are hardy perennials that can grow up to 8 feet tall. They are drought-tolerant and attract a variety of pollinators, making them a great addition to any garden.


How long do cup plant seeds remain viable?

Cup plant seeds can remain viable for up to two years if stored properly in a cool, dry place.

When is the best time to sow cup plant seeds?

Cup plant seeds can be sown in the fall or early spring.

How deep should I sow my cup plant seeds?

Sow cup plant seeds about 1/4 inch deep.

How often should I water my cup plant seeds?

Keep the soil moist but not waterlogged during the germination process. Once the seedlings have emerged, water them deeply once a week or as needed.

Do cup plants attract pollinators?

Yes, cup plants are known to attract a variety of pollinators such as bees and butterflies.