It all has to do with ground temperature......if anyone around you has a Forsythia bush, when it blooms out, the ground is warm enough for weed seeds to germinate....therefore, it's time for pre-emergent. I'd feel safe in suggesting you to do it now........

Ground temp and rainfall. Once the ground is warmed up from winter (such as it was), then the first rain is when you apply. Sometimes forsythia is late.

Agree - go ahead and do it now for Kentucky. I am in SC and probably should have done mine 2 weeks ago. :(

Thanks for the replies everyone. Tomorrow the lawn gets the Scotts and then later this year its getting some broad leaf weed killer. My yard is in shambles!

Hey Wilsocn..... I'm in KY too. Have you applied your Scotts Halts yet? We moved last Spring, I did nothing then, no time. I'm just now getting ready to apply Scotts myself but this time I'm getting the one marked 'Super' on the bag.... has 6 parts more nitrogen. I wonder if this will make a difference, guess I'll see. I'm concerned, due to the mild winter here, I'm a little late but it will surely prevent some of the crabgrass.

I put Dimension down last week and I am in St. Louis. Temps have been staying in the 60's. I usually use 0-0-7 because it is not good to put Nitrogen down this early in the season.