While digging out a dying dogwood tree stump, I discovered that the soil in my yard isn't exactly what I would call healthy. The top 5-6" are pretty hard and difficult to get a shovel through (though it does look like "soil"). Below that it gets worse, turning to rocky sand that broke a tine off my hand cultivator and bent my hand trowel. (Both of those were in use because it was just too difficult to dig with a full size shovel.) In addition, during the entire time I saw only 3 earthworms. This is a "new to me" house, but I do not believe there have been any chemicals on the lawn for many years (maybe ever) and the previous owners didn't seem to care much about the lawn (or trees or plants or anything).
I have lurked around long enough to know that I need a soil test. I did the Drainage Test and indications are that I need a LOT of organic matter in the ground. I would do the jar test for organic matter, but I think the results would be predictable.
What are my first steps? What's the fastest way to get a lot of organic matter into the ground with no resident population of earthworms? Should I do the baby shampoo treatment? Should I core aerate the bejeezus out of the lawn and then rake away the cores before topdressing with 1/2" of compost & trying to sweep it into the holes? Should I dig all that dirt back out of the dogwood hole and fill it with rabbit poop, compost, & worms and hope they spread out?