I'm working with a 6 acre church campus that has lots of trees, curbs, bldgs, etc. All need constant and frequent edging and trimming for neat appearance. I've finally figured out the way to go is probably using herbicide for border control. New to this part, so my question is: are there concentrated herbicides commonly available we can cut with water to provide more juice? Reason I ask is that, if we have to buy it in gallon containers at Home Depot, Lowes, etc, it's going to get expensive fast. So, what's the least expensive way to go, here?