Able to biodegrade, or break down when exposed to microorganisms under the right environmental conditions.

Compostable is defined as 'capable of undergoing biological decomposition in a compost site as part of an available program, such that the plastic is not visually distinguishable and breaks down to carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with known compostable materials (e.g. cellulose).' A polymer is "compostable" when it is biodegradable under composting conditions.

Capable of being broken down by soil microbes.

Materials based on plant or animal tissues that will decompose in the environment.