Well as I have no actual land to garden I can’t try this. Although I have used the concept to modify my cedar planters some. I have been finding that I really don’t need 18″ of soil in these planters as I am growing primarily salad greens, scallions and garlic in them. So I had been trying to decide what to use as a bottom layer to lighten up the beds and provide better drainage. Enter wood chips. One day recently I accosted the poor tree trimmers in my neighborhood for some wood chips. I put those fresh trimmings in the bottom third of the bed. So we shall see how it works out. I’m thinking that wood chips would be a great choice for a bottom layer in any container.