Another way to approach the business, and I'm not sure it would fly, but you could sell yourself as a handyman who would apply any of several various organic materials SELECTED BY THE HOMEOWNER. Oh by the way, you happen to sell those materials out of the back of your truck. So they could buy a plain brown bag of corn meal from you for twice what you paid for it, and you would apply it for $60/hour. You could carry a bunch of explanatory pamphlets to help the homeowner in selecting from the materials you sell. But the second you open your mouth to recommend something that isn't labeled for a specific purpose, you're in violation of some rule. One way of phrasing the benefits of certain materials that seems to fly around here is to carefully use the following words, "I use vinegar at my house to kill weeds," or, "Other people like to use corn meal to kill fungal disease," or, "Compost tea is popular on the Internet forums." In any case you cannot make a definitive claim that vinegar kills weeds because it has never been tested by any state approved organization. Your clients need to be absolutely clear on that. You might even have terms and conditions on a form they sign before you apply.

If you get into this business, good luck. There are people out to trap you. I would be very leery of anyone who acted a little hinky about signing, or who really pressed you to commit to the benefit to plants or even to the soil of anything you might sell or apply.

A couple keys to making money are
1. Don't sell anything for less than twice what you paid for it, and
2. Perform your services for the going rate of a local plumber. I picked $60 per hour, but if plumbers cost more or less in your area, you charge what they charge. That's what people expect to pay.

A homeowner can put most anything he wants to on his own lawn, except for certain herbicides, and, of course, nerve gas.