I have a lawn (3.5 acres) with a mix of k31, hounddog, and some other tall fescue mix from TS and/or Atwoods. Is there some kind of concentrated liquid preemergent I could spray on it which will hopefully save me some money over the granular preemergent? I'm trying to keep out mostly crabgrass, dandelions, sunflowers, and a few other weeds. Zone 6a. Thanks.