Compostable materials, like biodegradable materials, are broken down by microorganisms, but with a key difference: the broken-down matter must enhance the nutritious quality of the soil without introducing any toxicity.
Also, this entire process must take place within 12 weeks for a material to be considered compostable. Commercially produced compostable products (such as the compostable cutlery, cups and plates used by many restaurants) need to be sent to an industrial composting facility in order to biodegrade, where adequate conditions (such as temperature, humidity, etc.) are maintained.
They will not break down in a home compost pile or a landfill.
