Has anyone ever used strawbales instead of sticks or stones for the walls that form a keyhole garden? I realize the thickness means losing valuable planting surface, but I'm thinking one could channel the top of the top course to be half a deep and the interior will act as compostable material and moisture retainer for the bed. You could even plant pockets on the outside of the "walls". Eventually the whole garden will turn into a mound rather than being a permanent structure. Just curious what people think of this idea?
Why not try it if you have the space and access to organic strawbales. I would just verify that the strawbales have not been sprayed with chemicals as they could kill your garden plants.
To profit from the space of the bales, you could make pockets of soil in the strawbales and plant strawberry plants that hang over the outside sides of the strawbales and thus the strawbales becomes the growing structure too. Multi-stacking function of your strawbales.