Originally Posted by greendoctor
Hence my refusal of lawns that are not irrigated correctly and mowed at the wrong height for that grass. Modifying the irrigation timing/scheduling-FIRED.
I learned a lot of NEW cuss words doing that last year. Beneficial for swearing the three different languages. To the original poster, there are chemical for your problem but sadly not for residential use. Do you know your target weeds? Some of them may be just winter variety and will die down when the weather changes. As pointed out by Greendoctor, that St. Augustine should be mowed at 4" which will smother a lot of the Bermuda and combined with a good Pre-Em like "Gallery", things should begin to change. Personally, I would doctor the St. Augustine when it get warmer and grass begins to flourish with "Image" DO NOT USE ON DORMANT ST.AUGUSTINE--IT WILL KILL IT.