Are All Plant-Based Bags Compostable?
Table of Contents
Many bags today are labeled as plant-based.
This often leads to the assumption that plant-based bags are automatically compostable.
That assumption is not always correct.
This page explains whether all plant-based bags are compostable, what “plant-based” really means, and how to tell the difference using recognized compostable certifications.
What Does “Plant-Based” Mean in Packaging?
“Plant-based” only describes where the raw material comes from.
It means the material is made partly or fully from:
- Corn
- Sugarcane
- Starch
- Other plant sources
It does not describe:
- How the material breaks down
- Where it breaks down
- Whether it meets composting standards
A bag can be plant-based and still behave like conventional plastic.
Does Plant-Based Automatically Mean Compostable?
No. Plant-based does not automatically mean compostable.
Some plant-based materials:
- Do not break down in composting systems
- Break down very slowly
- Require specific industrial conditions
- Do not meet compostability test standards
Compostability depends on material behavior, not material origin.
Why Some Plant-Based Bags Are Not Compostable
There are several reasons:
- The polymer structure may resist microbial breakdown
- Additives may slow decomposition
- The material may not fully disintegrate
- Residues may remain in compost
Because of this, plant-based content alone is not enough to claim compostability.
What Makes a Bag Truly Compostable?
A bag is considered compostable only if it meets recognized compostable standards.
These standards test whether a product:
- Breaks down within a defined time
- Leaves no harmful residues
- Supports safe compost quality
Common compostable certifications include:
- EN 13432 compostable certification (Europe)
- ASTM D6400 compostable standard (United States)
- OK Compost HOME and OK Compost INDUSTRIAL
Learn more about certification scope on our Compostable Certifications Overview page.
Plant-Based vs Compostable — Key Differences
Plant-Based vs Compostable Explained
| Term | What It Means | What It Does NOT Mean |
|---|---|---|
| Plant-based | Made from plant sources | Compostable or biodegradable |
| Compostable | Breaks down under defined composting conditions | Works in landfill |
| Certified compostable | Tested to meet a composting standard | Universal disposal |
This table highlights why the two terms should not be confused.
Can a Bag Be Compostable Without Being Plant-Based?
Yes.
Some compostable materials:
Are partly bio-based
Are blended materials
Are designed for composting performance first
Compostability is determined by how a material behaves in compost, not by whether it sounds natural or renewable.
Why This Distinction Matters for Waste Systems
When non-compostable plant-based bags enter composting systems:
- They can contaminate compost
- They may be screened out and landfilled
- They increase processing costs
This is why composting facilities and municipalities rely on certifications, not marketing claims.
See why unclear claims are rejected in Why Councils Reject Biodegradable Bin Liners
How to Identify Truly Compostable Bags
To identify compostable bags correctly:
- Look for recognized compostable certification marks
- Check which composting system the certification applies to
- Avoid relying on “plant-based” or “eco-friendly” alone
If no certification is listed, compostability cannot be assumed.
Common Myths About Plant-Based Bags
Some common myths include:
- “Plant-based bags always compost”
- “Natural materials break down anywhere”
- “Plant-based is better than certified compostable”
These statements are often misleading.
Conclusion: Plant-Based Does Not Equal Compostable
So, are all plant-based bags compostable?
No.
Plant-based refers to material origin.
Compostable refers to tested behavior under composting conditions.
Only bags that meet recognized compostable standards should be called compostable.
Understanding this difference helps buyers, distributors, and waste systems make better choices.
