Do I need a footer for a small 3-block high x 5-block long retaining wall?

I'm putting in (actually replacing one that was knocked down by foundation workers) a small cinder block (or concrete block) retaining wall primarily to keep dirt back so it won't be "sluffing" over and getting onto a small concrete pad at the side door of my garage. I'm thinking such a small wall can be placed directly on the edge of the concrete pad and built up and out from there. What say you?