Simple, Sustainable, Low Water and Less-Work- That's the method explained by Paul Gautschi a professional Arborist in the video: Back to Eden, (you can view it on the internet for free. We've been experimenting with this method and are very happy with the results so far and are convinced things will keep getting better. It's especially nice that a so-called waste-product can become so useful and at the same time reduce my dependence on purchased soil additives and ammendments. Bonsall's Essential Guide to Radical, Self-Reliant Gardening is full of many sustainable and inexpensive ideas as well. Both men agree the soil/earth needs to be covered.