Coffee Grounds over clay base?
In placing my new raised bed, I took off a few inches soil, down below the weed root layer. This has left me with my bed sitting on clay (Southern California) and a four inch gap below my 12" sides (Sunset plan). After researching various soil amendments and weed barriers, I wondered whether anyone had experience using coffee grounds as fill.
My brainstorm was to collect coffee grounds from coffee shops, dig it into the clay a bit, fill to the bottom of my planter, place my hardware cloth along the bottom, then fill with the actual soil. That is, clay then a layer of grounds, then the soil.