I just built wood fence with a low 1.5' retaining wall at the base. The
posts are pressure treated 4x4's spaced 7' apart and held in the ground
with concrete. The wall is made of concrete retaining wall blocks
that run between the posts up to the bottom of the fence. Before filling
in soil behind the wall, I want to do something to keep the soil off of
the posts. One thought I have is to mound up gravel as a barrier between
the soil and the posts. What are the chances this will be effective? Any
other ideas?

Kevin