Your local extension agent will also have kits you can send to the state ag college for testing. We've had good input from doing that. I suspect the students run the tests. The first year after we bought this property, we were literally only able to germinate 3 kinds of weed seeds, nothing else. We sent off a test and it came back with a pH of 9.9! Plus, the proposed veg garden area had housed a horse corral and was "nearly toxic" with phosphate or phosphorus - I can never keep those two straight. Anyway, the "P" in NPK. This was from the horse manure. They sent along a handwritten note to not add any kind of manure for several years and then only after another test. We've worked hard for many years to get the pH levels down to where wanted plants will grow. It was a steep learning curve, but we've got a great garden and a nice lawn. I still have to work at it, though. Lots of organic matter helps, and selected extra applications of nitrogen to temp. lower the pH so plants can take up minerals is an ongoing task.