Question
I live in Pittsburgh, Pa, and my yard is being taken over by a grass that is not a single blade type.  It's like dead underneath, but on top there are  balls of grass attached, and it is very easy to just yank out handfulls of it.  Last year I planted a Pa mix of grass and was told it was good stuff, I think that it's awfull!  Is this stuff a weed or a grass?  Thank you for your help...  

Answer
Good Morning Frank:

From your description I am making a guess that the weed is annual bluegrass.
I am giving you three web sites that may help you but it doesn't look good as far as control.
Unfortunately some seed mixtures include annual bluegrass. If you still have the package, read the label to see if it appears there.
The last web site is one that will help you in regard to weed identification and control options on annual bluegrass and others that you may experience.

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7464.html

http://www.weedalert.com/weed_pages/wa_annual_bluegrass.htm

http://www.ppws.vt.edu/scott/weed_id/poaan.htm

http://www.psu.missouri.edu/fishel/ornamentals.htm

If the weed in question is not annual bluegrass and you can make an identification using the last web site get back to me and we can work on it then.

Have a good lawn.
Floyd McMahon