Zinnias are colorful annuals that bloom prolifically from spring to frost. It is easy to harvest zinnia seeds from your favorite plants and grow new plants. Seeds from hybrid zinnias will not produce the exact same type of plant, but will produce variations of the parent plants.
Use garden snips to cut completely dried flower heads from healthy zinnia plants. You can also snap the flower head from the stem with your fingers. If you snap a flower head off, you should hear a "pop" if it is ready to harvest.
Tear the flower heads apart over a piece of paper. Zinnia seeds are in the cone behind the petals. Check the base of the petals for attached seeds. The seeds look like fuzzy or furry tiny arrowheads.
Separate the trash from the seeds by pouring the seeds from one cup to another in front of an electric fan. This will blow away the lighter debris.
Spread the seeds out in a cool dry place until they are completely dried.
Put the seeds in a paper bag. Place the bag and a tablespoon of silica or other desiccant in a container and close tightly. Store in the refrigerator until ready to plant.