The phlox needs a cold--warm--cold--- oscillating temperatures.
I have not had much luck with fall sowing.
I think I am better to wait until
March, and sow seeds that need stratification then.
My winter sowing is usually done then.
Over the bulb plantings I scatter For -get-me -not seeds and
Siberian wallflower seeds.
Calendula, Sweet William and Iceland poppies sometimes work from a later fall sowing.