The Truth Unveiled: Are Compostable Plastic Bags Truly Compostable?

Are Compostable Plastic Bags Really Compostable?

In recent years, there has been a growing concern regarding the environmental impact of traditional plastic bags. As a response to this, compostable plastic bags have emerged as an eco-friendly alternative. However, one question that often arises is whether these so-called “compostable” plastic bags are truly compostable. In this blog post, we will dive into the world of compostable plastics and explore their actual composting capabilities.

Understanding Compostability

Before delving into the specifics of compostable plastic bags, it’s crucial to understand what “compostability” actually means in terms of materials. A material can be considered compostable if it undergoes biological degradation within a specific timeframe under controlled conditions.

The Difference Between Biodegradable and Compostable

To avoid any confusion, it’s important to distinguish between “biodegradable” and “compostable.” While both terms imply some level of environmental friendliness, they have different implications:

  1. Biodegradability: This refers to a material breaking down naturally over time through the action of microorganisms or other natural processes.
  2. Compostability: Unlike biodegradability, which can occur under various conditions (even in landfills), materials labeled as compostable require specific conditions such as high temperature and humidity found in industrial or home composting facilities for proper decomposition.

The Certification Process for Compostability

In order to label products as “compostable,” manufacturers must meet certain standards set by organizations like ASTM International or the Biodegradable Products Institute (BPI). These certifications ensure that products undergo rigorous testing before being deemed compostable. The certification process typically involves assessing the biodegradability, disintegration, and ecotoxicity of the product.

Composting Compostable Plastic Bags

While compostable plastic bags may be certified as such, it’s important to note that they cannot simply be tossed into your backyard compost pile or regular trash bin. For these bags to decompose properly, specific conditions must be met:

  1. Temperature: Industrial composting facilities maintain high temperatures (around 140-160°F) necessary for breaking down compostable materials quickly. Home compost piles rarely reach these temperatures consistently.
  2. Moisture Levels: Compostable plastics require a suitable level of moisture for proper decomposition – usually around 40-60% humidity.
  3. Airflow and Oxygen: Adequate airflow is crucial during the composting process. This allows microorganisms to thrive and break down organic matter effectively.

The Benefits and Limitations

The use of compostable plastic bags has several benefits when used in appropriate settings like industrial facilities or home gardens with dedicated compost piles:

  • Eco-friendliness: Properly managed composting facilities can turn these bags into nutrient-rich soil amendments without harmful environmental effects commonly associated with traditional plastics.
  • Diversifying Waste Streams: Incorporating certified-compostable products helps divert waste from landfills while promoting sustainable waste management practices.

Nevertheless, it is essential to recognize their limitations:

  • Inappropriate Disposal Methods: If not disposed of correctly (e.g., in a regular trash bin), even “compostable” plastic bags can end up in landfills, where they won’t degrade as intended.
  • Compatibility with Existing Systems: Compostable plastics may not be suitable for all composting facilities. It’s important to check if your local composting facility accepts these materials before sending them there.


While the label “compostable” suggests a more sustainable alternative to traditional plastics, it is crucial to understand what it truly means and how to handle such products appropriately. Composting requires specific conditions that might not be met in home settings or certain waste management systems. If you’re considering using compostable plastic bags, ensure proper disposal methods are available nearby or explore other eco-friendly alternatives like reusable bags or reducing overall consumption. Together, we can make informed choices towards a greener future!