Question
Tom,

Looking to change my centipede lawn to st. augustine.  I have a relativeley small lawn so the amount of sod is not an issue.  however, I dont know how to get rid of the current grass.  should I till up the centipede and lay down the st augustine or plug the centipede throughout.  I dont feel like waiting years for the st. augusting to take over.

Answer
Dusty:

The centipede will persist unless you kill it.  Roundup or like will do a good job, just not a perfect one.  There may still be some roots which revive and grow after St. Augustine is installed.  You may apply Roundup twice after waiting a month or so in growing season.  These summer grasses grow when temperatures are above 80-85 deg. F.  Spray after the daytime temps reach that mark.

After you are satisfied that centipede is gone, plant St. Aug sod.  There is no easy way to treat centipede after other lawn is planted.

Best wishes.