Fetilizer ?

[Fire/Grass]

Ok, I'm thinking about doing some fert. this year. I only do residentual lawns. So, my question is do I really need a license to put down fertilizer that I can go pick up at home depot and put on my own lawn. If I put the same stuff on a customers lawn I'm all the sudden illegal? Please tell me how all this works!

Thanks

[Scraper]

Look at the first post for Ohio. Your answers will be there.