When you are working with the crappiest soil you can think of, the best magic bullet is to add copious amounts of compost.
Gardeners that are worth their snuff know this, but landscapers don't always know this. Imagine you are to design a new home where all you have is the sub-soil and you are expected to make a fabulous landscape. You can, of course, make a fabulous landscape, but it will be fabulous for a very short period of time. So send out that bill quick.
When all you have is sub-soil, the simplest remedy is to amend what you have with lots and lots of compost. Sort of like turning it into topsoil. Compost should be applied yearly at least until your soil shows signs of biological life.
PS - Does anyone know what kind of spider this is up at the top of the post? It was probably about the size of a nickel, found near Hudson, WI.