Stop with the fertilizer. Perhaps something has been eating the buds?
Linda C

Jonnie, did you start them late? Cosmos needs short days to bloom. If you started them late, the days have become long, so it will actually take them longer to bloom. They will more likely bloom when the days are starting to get short again.

Cosmos are sensitive to day length. If you search the internet for "cosmos day length" you will find a lot of information related to this phenomenon.

This is my first year to grow cosmos, they have been blooming since June, they are growing and in great shape
no fertilizer and just water some fromt the sprinklers.
My sister did not fertilize hers either and they too were
great bloomers. I don't know the name as I got them from some one in trade. They are mixed colors. Lovely for my
first ones. I would say they dont need fertilizer.
caroline

For got, mine are in full sun, all day , ever day

Every year, I have the same thing happen. My cosmos reseed easily in the garden. Most grow quite healthy and start to bloom around August. I'd say about 50 percent of the plants don't bloom though. They are the most vigorous looking plants, with the most foliage, but no flowers.

I have two cosmos plants with no flowers among a few score that are blooming. Same seed planted and cultivated in the same way.