My lawn seems to need to be dethatched. Here in the Mid-Atlantic, we are
still in the hot season and my turf-type tall fescue is hanging on but not
thriving.

Should I do it now or wait a month or so for the cooler weather ? Seems
that less thatch might help the fescue "breathe" and minimize humidity
related problems like mold.

I'm afraid that spiking or dethatching might just help the Bermuda grass
thrive. I consider Bermuda to be a weed and it comprises between 1% and 20%
of the yard depending on the location.

Any thoughts ?

Any ideas on how to keep Bermuda in check ? I'll never get rid of it
considering the size of my lawn and the ubiquititous nature of the stuff. I
occassionally kill big areas of it and overseed.

Thanks