I have an old metal farm building where I grew grapes against 2 walls until the animals ate the tops off 3 years ago. Why and how that caused me to have worthless vines ever since is another subject. I quit pruning so the vines pretty much covered the building over. In preparation for grafting a new grape I tasted this year,I set about removing the overgrown vines back to rootstock. Where the vines laid on the roof and caught dust and fallen leaves there was a 3 inch layer of unbeleable compost. The texture was more like worm castings than compost. I give you my word that not once did I go on the roof to turn,amend,water or otherwise worry with it. We have had drought conditions the passed few years and it does hit triple digits in Texas several days each year. I wish those who suggest composting is an art to be studied and mastered could have been present.