The seeds will range in size depending on the variety of zinnias you are growing, but most will be brownish in color, have a slightly furry texture, and will be somewhat flat and either rectangular in shape or shaped like tiny arrowheads. To identify the seeds, follow the petals down to their base. The seeds will be located in cones just behind the base of the petals.
After removing the heads from the stems, "cure" them on a tray for a few days in a dark, dry area before storing them in a paper bag and sealing them in an airtight container until planting. If you want offspring with the same genetic traits as the parent plants, it's best to grow and save the seed from heirloom varieties. On the other hand, saving seeds from hybrid zinnias will assure you a random mix of genes that may result in flowers with some very interesting characteristics. In either case, strive to save the seeds from only the hardiest flowers with the longest lasting blooms and the most vibrant colors.
By likekinds from NC
I've tried crushing dried mixture and dropping through wind of a fan. The heavier seed should fall straight down and petals blow away. I am going to try washing dried mixture in a bleach solution to kill any fungus and screening. Maybe an old washing machine will work as I have large amount to do.
When bloom dries on stem harvest and cut down petals to inner cone before separating seed from flower head. It's a lot less time consuming then doing each individually.
I would like to know how to collect zinnia seeds from the flower heads?
Hardiness Zone: 4a
By tjc47 from MN
Use a wire tea strainer. Put the flower heads in the strainer over a container, pan or something to catch the seed. Mash with hands. You can see the tiny seed, store in paper bag or if they are very dry in a zip lock bag, good luck.
It's simple. Just let a few flower heads dry on the vine, run your thumb through the center, and voila, hundreds of seeds. Place in an evelope and label. Plant in the spring after danger of frost.