Rubble in the border
My brother in law, who obviously knows everything, has me second guessing myself. I have built a small retaining wall in my mother in law's garden intending to fill it with rocks, compost, the Camellia, Peonies etc. He has filled it with old cement, blocks and render from an old wall and claims that if I just top it off with compost the plants will love it. I'm not off my head am I? He's barking isn't he?