I can confirm that chemical weed killers do not work. I am not so sure that they do not work on all weeds anymore because of the plants but I think environmental codes have demanded they remove some of the more dangerous chemicals. I sprayed poison ivy with Roundup and it acted like I gave it some fertilizer.
I use the vinegar and salt and that works. I have a long hot sun all day walkway that I cannot pull the weeds between the bricks without getting heat stroke.
I pour a box of salt followed up with vinegar poured between the bricks. That keeps them down for about a month or two if we do not get a lot of rain but the quake grass, wild oxalis, Purslane comes right back before summer is over.
So if pouring a layer of salt and vinegar chaser does not make that crack sterile for life I do not see how it could possible hurt in the soil anywhere else.
Okay here is more proof. This was a property that had not been cared for for years because the owners were elderly and could no longer care for 4 acres. I had a very large job ahead and I wanted to do it with as little hired help as possible. So I started with areas. This was outside the back door area that I poured (yep poured 3 bottles of vinegar, and sprinkle one box of salt, and covered with cardboard. Had lots of cardboard boxes from the move. Over that cardboard I put all the Fall leaves from the yard. The following Spring I planted my hosta that I had moved from the old house that were in pots all winter waiting for their new garden.
You can see there were still some weeds that did not care if they were vinegar, salt, cardboard covered they were coming through.
and so you can get a real feeling of how big this area is nothing like a winter pic to show
