You may have already started seeing crabgrass and other summer annuals in the cracks of your sidewalk or driveway. This is an indicator of the weeds that may soon infiltrate your lawn. You should have already received a first application of pre-emergence. A second application will help reinforce the pre-emergence barrier, and therefore prevent many of these weed-seeds from taking root and infesting your lawn.
The pre-emergence window is coming to a close. Act now and keep that nasty crabgrass out!