Ah, weed killer! Another thing that works for places that you NEVER want anything to grow again is rock salt. The kind for water softeners or for spreading on walks when it snows.

We use it in the horseshoe pits and on the driveway. I really don't know how much to use per sq ft, I think we've used it with about a 1 bag per 5-10 sq ft. Don't use in flower beds, and it can leach into surrounding soil and kill the grass, etc. Once a year, in our vegetative-free zones, it definitely keeps the weeds to a minimum.

We go pretty lightly with it, so it doesn't leach and kill the lawn and plantings, so after 6-10 mos or so, the rain dilutes it, and we get some regrowth. We are on city water, and our aquifers in the area are contaminated with all sorts of chemicals so salt leaching in is the least of our worries, but anyone with good clean well water should do their research as to if/how this could affect their well or aquifer.