I am not a licensed professional, but I can read a product instruction label and my new Kentucky Blue is being invaded ! Region : SE MI I used Spectracide Weed and Grass Killer several weeks before new sod was installed. It sure looked dead dead to me before the installer arrived ! We have had a very warm summer (record number of days above 90) and the new sod has been well watered. After a few weeks yellow nutsedge and (I believe) quackgrass started popping up through the new sod. I also believe I have some Bermuda bluegrass. Installer had no advice. I know from past experience that typical "big box store" purchased selective herbicides won't touch any of these weeds. Internet research lead me to this site and Certainty. It is being sold online. The last thing I can find here is that use of Certainty on "cool weather grasses" (KYB) is not approved by Monsanto despite research done by some universities showing that it is effective. What say you experts ? Or should I just cave in and hire a commercial company (TruGreen?) and hope they have "the right stuff" to control these weeds before they take over my new sod !