Ruth,
Unlike most other flowers, zinnia seeds can be collected before the flower has turned brown. If you pull out the basal petals and they have a thickened seed at the end, you can harvest them while still green and let them dry a bit longer than if they were brown already. I was skeptical when I first heard this, but that is how I collected my seed last year and I had excellent germination this spring.

Martha

Martha,

Thanks! It just seems so weird that they're not turning brown. But on the most faded one, I pulled a few petals out today, and the seeds look like they're maturing.

My Oklahoma Zinnias have the same experience. I love this variety and really want to save the seed from some of the nicer plants. The heads seem immature after spending three months on the stem. With the upcoming freeze I am hoping they will mature to ripeness inside in a paper bag. I think the cool and cloudy weather is to blame for the slow maturity of the seed heads. I have had trouble obtaining viable zinnia seeds in past years and hope this yield will work out.