I know I will probably get lambasted for this but I will tell it anyway. I have a customer who does not use fert on her lawn. We have tons of rain up here in Michigan and each Monday the lawn barely needs a cut. In July and August, I'm afraid it wont grow one bit. I have a limited customer base right now, first year in the business. She was gone last week so when I mowed, I tossed down some fert out of my pocket to hopefully get the grass to grow a little bit. I noticed this past Monday the yard was a little longer so it appears to have worked somewhat. Should I get her to use fert that I put down or just do it every once in a while when she is gone and pay it out of my pocket and then next year get her on a fert program? She is gone once a month on Monday's for doctor checkups so I know I can toss down some fert on those days.