Bev, you are probably right, mine have not made any seeds, double white either...other cosmos made a few seeds at first, think in May, so we can blame it on the heat and humidity.
" Bright Lights" Cosmos is having plenty of seeds though!

I think that different varieties of cosmos produce different quantities of seeds, and like graanieb said, Bright Lights is a good producer of seeds.

I suggest just keeping a good eye on any cosmos and get what you can from them as they dry, before something else gets them, or they fall.

Sue

I have the white Double Click Cosmos and they not only produce fewer seeds, they are relatively small. I almost threw seeds out with chaff.