Biodegradable vs. Compostable

Is Biodegradable and Compostable the Same Thing?

Though they may sound like the same thing and are often conflated, “biodegradable” and “compostable” actually have different meanings.

All compostable items are biodegradable, but not all biodegradable items are considered compostable.

Characteristics of Biodegradable Material

Something that is biodegradable can be broken down by microorganisms into simpler organic materials. This process can take days, weeks, months, or even years. Biodegradable items can break down completely but may leave behind residues in the decomposition process.

Unique Characteristics of Compostable Material

Similarly, something that is compostable can be broken down by microorganisms into simpler organic materials. But this process occurs more quickly and creates a substance called humus that is full of nutrients for the soil, without leaving behind residues or chemicals.

For this reason, compostable materials are often used in commercial composting operations. While definitionally, this difference may seem subtle at a glance, there are big variances in terms of eco-friendliness.

Biodegradable (but not compostable) Material Examples

If we take a look at items that are not compostable, but still meet the requirements to be considered biodegradable, we see items that typically take a long time to decompose.

• Leather
• Bones
• Coated paper packaging
• Cloth bags
• Disposable coffee cups

Compostable Material Examples

• Banana peels
• Apple cores
• Coffee grounds
• Yard waste such as grass clippings
• Eggshells

A great example of a product that is both biodegradable and compostable is our trash bags! These are suitable for at home composting because they’re entirely made from corn starch.

Is the Difference between Compostable and Biodegradable Important?

The difference between these two labels is actually very important. “Biodegradable” includes an extremely wide range of products that vary significantly in time to decompose.

The list of compostable materials is much smaller and they’re more alike in terms of the process and how quickly they can break down.

By introducing non-compostable items into a composting cycle, it can be extremely disruptive, even if the added materials are biodegradable.

Not only can it interfere with the speed of decomposing, but can add in potentially toxic residues as it breaks down. These residues can be harmful for many compost uses such as gardening.

These differences and potential risks led to the creation of several policies and regulations such as the European Standard EN 13432 [1] and the ASTM D6400-99 (USA) [2], which lay out criteria for an item to be considered “compostable”.

Is Compostable Better than Biodegradable?

In terms of ability to decompose into pure substances and return to the earth, yes, compostable is better.

However, there are of course different purposes and functions of different materials. Some products simply can’t be made in a purely compostable manner. If there is an equivalent compostable version of a product, it’s best to go for that one.

Just because an item isn’t compostable doesn’t mean that it is bad. Be sure to look into an items reusability and recyclability in addition to its ability to decompose.