Garden soil is a ready way to start a recipe. Good dirt straight from the top few inches of your garden has trace nutrients and minerals that help balance a blend. Don’t use it by itself because it lacks the drainage required for containers.
Rock dust helps you mimic native soils. This powder made of pulverized stone contains trace nutrients and minerals from bedrock, the natural source material of all soils. Get it free at a local quarry, or buy a 5-pound bag from mail-order sources.
Peat moss holds moisture, adds nutrients, and increases soil acidity. A compressed bale, available from garden centers and agricultural suppliers, will last the average home gardener several seasons.