The Grass Doctor

How long until I see results from applying pre-emergent crabgrass killer?

I live in Michigan, Mid western, and I put down a pre-emergent crabgrass killer and lawn food about a month ago. There is allot of crabgrass in the yard. Along with some new grass growing from overseeding last year. My question is..........how long until I can see the results? Did I apply at the proper time? It said on the bag to apply anywhere from March to May. Also that it could be applied up to four weeks later than other products. Crabgrass is still there. Do I need to pull it up by the roots or wait it out? If I pull it up.....OMG.... no way! There is allot of it. Thanks

Public Comments

1. Don't fret. Next year you need to lay the pre-emergent earlier. In Oklahoma we lay pre-emergent when Forsythias bloom, which is at the beginning of March. Also, you can use a chemical called MSMA to kill the crabgrass without hurting the grass if you have a warm season grass like Bermuda. This probably doesn't apply to you in Michigan, however.
2. I am not sure, If it is as you said a Pre emergance herbicide, then maybe you should have applied it prior to emergance of the grass