It is actually on a slight slope. I put down landscape fabric under the whole thing. I dug holes and put large cattle lick tubs in to hold my Russia sage, Iris, and grasses from spreading. I don't have a problem with it draining. I am thinking about planting more plants in there this year. I will have to move the rock and cut the fabric where I want to place the new plants. I will update in the future with pictures when I get it done. I don't really water this bed. I leave that up to mother nature but if I add more plants, I may have to start watering it during our dry times.
