Ideas For Collecting Cosmos Seeds

Saving cosmos seeds from your cosmos blooms in the fall will save you money and enable you to plant these tall, colorful flowers promptly in the spring. Use these ideas to collect and store your cosmos seeds for 6 months to a year.

When to Collect Cosmos Seeds

Wait until the cosmos have finished blooming and the petals have fallen away from the central seedheads. The drying seedheads should be dark brown or black in color instead of yellow. Choose a warm sunny afternoon to collect seeds, to prevent mold growth from damp seedheads and seeds. Pull the seedheads carefully off the flower stems over the large cardboard box, and place the seedheads in the box as you collect them.

To keep the same color of the flowers for next spring, collect seeds from each color of cosmos you have in your garden separately, and dry and store them apart from the other colors. Label them by color to prevent confusion when planting again.

How to Collect Cosmos Seeds

Use your patio table or set up a small folding table in the garden. Cover it with newspaper and then with plain white sheets of paper taped together. If you drop seeds from the dried seedheads, you will be able to find them on this white cover. Bring out small containers to use as seed collectors. Plastic tubs with snap-on lids work well. Pry open each seedhead over a container to release the tiny seeds. Brush inside the seedheads with your fingers to ensure you have all the seeds from each. Pick up any that fall onto the white paper.

Drying the Seeds

Transfer all the seeds into the cardboard shoebox and leave in a dark, cool place for 6 to 8 weeks so they air-dry thoroughly. Shake the box every week to turn the seeds and keep them from sticking to the inside of the box. Check to ensure they are drying on all sides and turning dark. When they are fully dry, put them into a plastic zip-top storage bag, either sandwich-size or medium freezer size. Label the bag as "Dried Cosmos Seeds" so you can identify them next spring. Write the date on the bag, as you can store these dried seeds for over 6 months.  Keep them in the dry, dark, cool place where you dried them out. Avoid exposing them to any light while they are dormant. If you need to store seeds outside, put the bag into an old, completely cleaned paint can with a snug-fitting lid, to guard your seeds against chewing rodents.

Collect and store seeds from your cosmos every year to assure yourself of the freshest seed stock to plant every spring. If you build up a large supply of seeds, give them as gifts to friends during the winter holiday season, so they can add them to their gardens in the springtime. Looking forward to having these beautiful flowers in their garden will help keep their spirits up through the long winter months.