Raised bed gardening is really the way to go, particularly if your native soil is terrible with clay, rock, or sand. With raised beds, you control the quality of your soil, leading to healthier plants and a better harvest. The only problem is that filling those raised beds with high-quality soil can be pretty expensive — but as a gardener, you know that everything starts with healthy soil, and you don’t want to cheap out, right? Fortunately, there’s good news for both the conscientious…