I bought a number of "half" clay bricks. They are reclaimed bricks cut in half longitudinally, about 2"x2"x6" long. Some of the bricks have old gas company name stamped on the sides.
I will be using these bricks as a landscape edging to delineate between grass lawn and a planting bed. The bricks will only be stacked two (at most three) high.
I made a 3" wide trench along the border, only an inch deep, compacted the bottom with a 2x4, wet it down, then I mixed some cement mix and pour that into the narrow trench. Then I set the bottom layer of bricks into that one by one. That will secure the first row of the bricks which will be mostly invisible when the grass grow back.
Now what should I use to attach the second row and if necessary the third row? Are there any strong and effective adhesive I can use for this? Basically to keep them in place if lawn mowers hit against it, or someone kicks it or whatever.