I have just had the old rotted wood deck that was around my inground pool pulled up. I had been battling constant grassy weeds, nut grass and trumpet vine invasion in the spaces between the deck boards. The fence line along the pool is covered in trumpet vine, which is pretty, private & invites the hummingbirds, but the most fast growing and invasive plant I've ever seen Instead of wood, I am replacing deck with 4" of sand and a 2" topping of river rock. I plan on treating all the exposed weeds/vines with a good vinegar, orange oil and soap mixture, but what can I put down before the sand gets moved in to help stop ANY plant growth in this area? Howard mentioned a product last Sunday that sounded like something I should use (sounded like it had salt in it), but I couldn't write it down because I was on my way to church.

I have heard Howard talk about 3-4 layers of overlapping newspaper will do the trick.