I just stored everything together last season, planted them this Spring, & got a "bumper crop" of zinnias. Repeating this year ... "if it ain't broke, don't fix it". :)

Ilsa

PC,

As Ilsa said, it's OK to save the chaff & petals and plant it all, but I usually separate them manually. If you have saved many seed heads, you could get rid of a lot of the light chaffy stuff by "dribbling" the mix onto a surface while gently blowing the light stuff out of the falling stream.

There may still be some bits of stems and flower base that you could pick out manually. It depends on how much time you want to spend.

There are two kinds of zinnia seeds; the kind that are attached to the base of the petals and the kind that are attached to the base of pollen florets. The pollen seeds are usually selfed, while some of the petal seeds may have been randomly pollinated by bees.

From time to time I experiment with zinnia breeding, just as a hobby. So a lot of my petal seeds have been cross-pollinated by me. For that reason, sometimes I separate my petal seeds from the pollen seeds and plant them separately.

If you had Bacterial Leaf Spot on your zinnias this year, your saved seeds may transmit that disease to your next year's zinnias. Bacterial Leaf Spot of zinnias is frequently transmitted on seeds. I am currently looking into ways to prevent that, such as some kind of seed treatment.

Rain can also splash the bacteria from the soil or an infected plant onto an uninfected plant. Some copper-based sprays can combat Bacterial Leaf Spots on zinnia plants.

MM