I put out Haltz crabgrass preventer without nitrogen (see link) in the middle of February... http://www.scotts.com/media/media/pdf/productGuide/labels/Halts.pdf and was wanting to put it out again in the middle of March to control the bad crabgrass problem I had last year. I also wanted to use it again this fall to prevent the winter weeds I had this past winter. But the directions say (see link) to only put this out 2 times per year. It doesn't have fertilizer in it so I would like to use it pretty often until I get a thick green lawn without the crabgrass and weeds. Why can't I use it more than twice per year? Will it hurt my Bermuda if I use it 3 or 4 times this calendar year? I bought this house about a year ago so I'm just now getting to use pre-emergent on the yard. The house is in Aiken, SC. Thanks for all your help!!! I'm new to the site and hope you can help...I just want to use this more than twice this year and I don't understand why I can't. Thanks again!