Select the proper material for compost. Different plants require special levels of soil acidity to thrive. Use materials such as bone meal for plants that grow better in alkaline or neutral soils and citrus rind and leaves for plants that require a more acidic soil.Verify the pH of the mixture before planting.sing compost instead of topsoil can require a layer from 6 inches for shallow root plants such as violets and oxalis to 12 inches for deeper-rooted plants such as petunias or ferns.