The Dervaes family makes their entire living from selling organic herbs and vegetables to local restaurants. If you don't live near a large urban area, but rather in a small town, you may only be able to make a partial living from this, but every restaurant would prefer fresh, organic herbs and veggies to store bought.
You will likely need some sort of license to sell what you grow, so check with your local licensing authority before you start selling, or fines may be steep. Also, check with the USDA to find out exactly what has to be done to be able to call your products "organic", as laws are very specific about labeling of products.