Well, obviously you can't mow for $20/hour and make a decent living if you're a legitimate professional, so you're going to have to expand your marketing plan. The customers are out there that will meet your rates, you're just going to have to talk to more people. Have you gotten flyers out yet? Do you have an ad in the newspaper/yellow pages? Asked your clients for referrals?
My old boss in sales (many, many moons ago!) would always preach about the law of averages. Whenever I'd come back to the office and complain that people aren't buying, he always told me I wasn't talking to enough people. He was always right. 1 out of every 10 people you talk to will buy dirt if you sell it. And sometimes you can talk to 99 people before the 100th buys 10 times the average amount, but it always bears out.
Stick with it, friend, and find a way to talk to more people!