I use more of a tried and true process. I water the lawn until I start seeing mushrooms. Then I taper things off. Touch the grass an hour after watering. If it is dry, you will need more water. Dialing in the right settings will take a lot of time. Summer is the toughest to gauge with spring and autumn a lot easier. We are constantly watering throughout the day and we have several schedules to keep the lawn green. It is a lot of trial and error, but taking soil samples is not going to do a lot of good. My lawn is on an inch of soil and sand and rock beneath. We easily have the best lawn in the neighborhood. Trial and error and best of luck!
