Now Sowing: Cosmos (September–November)

About Cosmos

Common Name: Cosmos

Scientific Name: Cosmos Sulphureus

Seed Saving Level: Advanced


Sow 1/4 inch deep, 12-18 inches apart after the fear of frost has passed. Cosmos like full sun and hot weather since they’re native to arid regions like Mexico and southern Arizona. They don’t mind drought, poor soil or a bit of neglect. Once established, they don’t need to be watered unless there is a prolonged drought. Cosmos germinate in 1-3 weeks and will begin producing flowers in 50-60 days. No need for fertilizer.


Cosmos is an annual with flowers atop a long stem that attract bees and butterflies to your garden. They make great cut flowers. Deadheading will prolong the flowering season.

Seed Saving

If you let the seed heads blow during the fall, cosmos will self-sow. If you want to collect seeds to store or share, remove the dried pods after the flowers have fallen off. Gently rub the pods with your fingers over a paper towel to separate the seeds. Pour into an envelope and let dry for another 6 weeks.