I built and installed two very large garden beds to be placed atop a new decomposed granite surface that was installed by a landscaper. The beds look great, but the water draining from the beds is being absorbed by the surrounding DG, making it look ugly. The DG holds onto the water for a very long time and is actually starting to mold in parts of the surface that don't get a ton of sun.

We are now underwatering our plants in the garden bed to limit the seepage into the DG, but that doesn't seem to help--we can go three or four days without watering the garden beds and the problem remains. Anyone have ideas for what we can do to fix the problem? Add more DG to create a deeper surface? Right now, the DG is about 1-2 inches thick and it sits direct on top of fairly compact soil (no weed barrier).