How do you prepare a garden spot in an impossible situation? My first step was to strip all sod and weeds off the bed. Then the soil was turned over. Since this was too difficult for me, I hired a neighborhood teenager. He worked for several hours for minimum wage. I simply had him turn the soil over the depth of the shovel and rake it smooth for me. This was my first summer of gardening and I didn't know I should add humus or compost. I learned the hard way! Three years ago I moved to a new townehouse where I faced the same conditions. I had the garden plot dug in the fall and covered the soil at least six inches of chopped leaves for the winter. In the spring, the maintenance man was kind enough to bring me a front end load of compost. Then I had some friends collect earthworms for the garden. Some teenagers created a cement block border to keep visitors out of the garden plot. The holes in the cement blocks were filled with a mixture suited for rock garden plants. When facing a west facing front yard, I again had a border created with cement blocks. Then maintenance dumped some good black soil on top of the exist, hard-packed clay soil. This was covered with leaves for the winter. I was able to plant well over a 100 new plants/shrubs my first spring in this new townehouse due to the Fall preparation. I've concluded that fall is the very best time to prepare new garden beds.