Your sleepers just aren't ready to say 'hello!'. In past years, my hostas, columbines, gaillardias and liatris have all germinated later than others. Just make sure the soil is moist and that the seeds are not sacrificed to the sun God. LOL!

If I resow, I do so in another container. I've never resown in the same container, but that's just me.

The gaillardia 'goblin' is popping up all over the container, but the others are just sitting there. I will be patient though and keep peeking in every day....or several times a day! LOL
gg