The best way to prevent crabgrass, is to apply a pre-emergent barrier in the spring, before soil temperatures reach 55 degrees. This chemical barrier will effectively stop approximately 80% of germinating crabgrass from becoming established. In the northern US, this means the application should be made by mid-April. To be safe, an earlier application is recommended. The most effective preventive program includes two pre-emergent applications; one in early spring and a second application later in the spring.
Moles and voles destroy plant roots by burrowing underneath the turf in search of insects, on which they feed. One popular myth proclaims that “grubs are the moles food; get rid of the grubs and the moles will disappear”. Unfortunately, this is not accurate. While moles do feed on white grubs, they also devour several other sub-soil critters; earth worms, for example. So, killing grubs, while it can be helpful, is not a complete solution to mole problems.
If your lawn has broadleaf [dicot] weeds, like dandelion and thistle, weeds must be treated when actively growing. Using a dry product, the material must be applied to moist foliage. That can mean watering before making application or rising early enough in the morning to apply product on a dewy lawn. Liquid controls use water to ensure weed coverage and contact with the blade, where the weed control is taken in and translocated throughout the plant for complete control.