I'm going to be building a tree ring probably this weekend on a tree I have in the front yard. It's a Japanese red maple, I think it's called. Right now there is one the previous owner put in a while ago, just white rock and ugly concrete edgers. So, I'm going to rip that out and put in a tree ring.
What I "think" I need to do is dig down 6" and make the foundation layer there. Make sure it's level and go from there.
Do I need to use construction adhesive between the blocks?
Do, I need to dig down further and put a couple inches of sand down as the foundation?