Minecraft wiki entry for Composter, associated text: The composter can be filled with compost, which is done by adding compostable items to it. When successfully adding an item, a green particle appears. The table below lists supported items, which have different levels of compost-ability. The higher the percentage of an item, the more likely it is for it to add another layer of compost. Each layer of compost has a podzol-like appearance. When the composter reaches the 7th layer of compost, the compost changes appearance indicating that bone meal can be collected by using the composter a final time.