Difference between biodegradable and compostable

Ever picked up a product labeled "biodegradable" or “compostable” and wondered what it means? You're not alone! 

The terms biodegradable and compostable are often used interchangeably. While there is some overlap, they do not mean the same thing!

All compostable products are biodegradable, but not all biodegradable products are compostable.

Compostable Definition: What Does Compostable Mean?

Compostable materials break down completely into their basic parts (water, carbon dioxide, and biomass). They will break down in a timely manner at a rate consistent with similar organic materials and will not release harmful residue or toxins.

Products labeled as compostable must be tested to meet US industrial composting standards ASTM D6400 and ASTM D6868. These standards require that compostable products biodegrade and disintegrate within 90 days and leave no harmful residue. Testing includes a seed germination trial, which ensures the compost produced is not harmful to plant life.

Compostable products add value to the planet's ecosystem by decomposing into nutrient-rich compost. Packaging that is labeled as compostable should be disposed of in a compost bin.

Biodegradable Definition: What Does Biodegradable Mean?

If something is biodegradable it can be broken down by naturally occurring microorganisms such as bacteria and fungi. Every material will biodegrade, given enough time (even centuries!).

Unlike compostable, the term biodegradable is not regulated. There is no time limit for biodegradation, and no testing is done to ensure that the product is free from dangerous toxins. Ideally biodegradable material will break down quickly and safely, however not every product advertised as biodegradable meets these criteria. 

A product labeled as biodegradable without any further context is vague and misleading to consumers. Because this term is so vague, biodegradable products may contaminate compost and should be disposed of in trash collection destined for landfill.