How to Make Potting Soil Select ONE OF EACH from the following ingredients. Use a wheelbarrow to mix thoroughly. PART ONE: A high quality garden soil (filtered through a screen) OR a commercial topsoil. PART TWO: Peat moss, leaf mold, OR compost. PART THREE: coarse sand, NOT vermiculite OR beach sand. Mix 1 part each of the above ingredients. Add 1/4 part bonemeal OR rock phosphate. Mix well. Add 1/4 part greensand. Mix well. Tips: For plants that prefer a more organic mix, use 2 PARTS peat moss, leaf mold or compost. For plants that require a medium that needs to stay dryer, use 4 PARTS sand, vermiculite or perlite. If you mix more than you can use, give it to a neighbor or store it away from drying winds and rain.