The more you earn money, the more you can spread fertilizer in the customer's yard to earn even more money. What an evil plan!
I ran into the glitch when I could buy grass growth updates infinitely so the yard was completely full of grass and my laptop started slowing down. I don't think the customer will be happy about that!
But it was a very satisfying idle game, and I felt like I had to continue playing until I fully upgraded every category. Well done!