I'd guess that Grandview knows what it is, but is actually asking "Okay, but why do you actually need one?", which is the same question I have.
Since Ohio is an at-will state, you can easily terminate them. In addition to firing them, do you also want to sue them for doing side work or prevent them from working in your industry and region for a set period after they leave your company? For a laborer?
If you want it more as a dissuasive scare tactic, draw up what you want and have it part of their employment agreement. If you want it enforceable, have your favorite local labor attorney draw one up for you, just be aware of the parameters and litmus tests that accompany them in Ohio. If you want to research it, Google "Ohio non-compete" or under the more precise "covenants not to compete".
a guy who knows both the lawn business and web strategy