For each wall, a trench must be dug and filled with a base of fine gravel. It is leveled and the first row of bricks must be carefully leveled. That first row is critical to the success of the wall.
The maximum recommended height for these retaining walls is just 24". We will remove some of the bricks from our first wall - realizing it has been built too high to hold well. We realized it also looks kind of strange.... We are so sore these days - from head to toe.