Most articles about plant fiber container compostability certification just list standard names like ASTM D6400 and EN 13432, add a line like “certified means it’s truly eco-friendly,” and stop there.
They don’t actually explain how the two standards differ, and they don’t tell buyers how to verify a supplier’s certificate is genuine once they have it in hand.
Our earlier piece, Biodegradable vs Compostable: What’s the Difference, and Why Some “Eco-Friendly” Packaging Belongs in the Regular Trash, covers the basic definitions of biodegradable and compostable. This guide goes one step further into the two specific certification standards themselves.
Where ASTM D6400 and EN 13432 Actually Differ
ASTM D6400 is a US standard set by the American Society for Testing and Materials. EN 13432 is the EU standard. Both verify whether a material breaks down under industrial composting conditions, but the regions they apply to and some of the testing details aren’t identical.
If your plant fiber containers are mainly sold in the US, your supplier will typically have ASTM D6400 certification ready. For the EU market, that’s EN 13432. The two standards aren’t interchangeable, they each correspond to a different market’s regulatory requirements.
Disintegration and Biodegradation Thresholds Aren’t the Same
Both standards require the material to disintegrate into fragments below a certain particle size within a set time under industrial composting conditions, then fully biodegrade into carbon dioxide, water, and biomass.
The difference shows up in the threshold details, things like the mesh size used for the disintegration test, the biodegradation percentage required, and the testing timeline. The exact numbers aren’t identical between the two standards, which is why the same material can pass one standard and fall short on the other.
Plant and Earthworm Toxicity Testing Requirements Differ
Beyond breakdown speed, both standards test whether the residue left behind affects plant growth or is toxic to earthworms and other soil organisms, confirming the material doesn’t leave harmful residue contaminating the finished compost.
The indicator species used and the toxicity thresholds differ somewhat between the two standards. If a supplier has only run toxicity testing under one standard, that doesn’t automatically mean the other standard’s requirements are met too, something that’s easy to overlook during procurement.
Should You Get Both Certifications for the Same Container
There’s no single right answer here, it depends on your market mix. If you’re only selling into the US, ASTM D6400 is usually enough. If you’re only selling into the EU, EN 13432 covers it.
The real complication shows up when you sell into both markets at once. Some suppliers only hold one of the two certifications, and the buyer on the other market only discovers the mismatch after the shipment arrives, which directly affects a distributor’s delivery timeline.
From a cost angle, requiring a supplier to get both certifications adds testing fees, which usually get passed through in the unit price. But if a shipment gets rejected by a retail channel in your target market over a certification gap, the cost isn’t just that shipment, it’s the time spent rebuilding trust with that channel.
Put another way, whether to require both certifications comes down to weighing the extra testing cost against market-access risk, not just picking whichever option looks cheaper.
How to Verify a Supplier’s Certificate Once You Have It
Which Fields to Check on the Certificate
Once you have the certificate, start by checking the issue date, the expiration date, and the certification scope, which usually specifies the applicable material, thickness range, or product category.
Certification scope is the detail most often overlooked. Some certificates are tested against one specific product spec, and if you’re purchasing a different spec within the same product line, it technically falls outside that certificate’s scope. Suppliers reusing an old certificate to cover a different spec happens more often than you’d expect.
How to Verify Directly With the Certifying Body
Most certifying bodies maintain an online lookup system where you can check a certificate number against their registry. If it doesn’t come up, or the registered information doesn’t match what the supplier provided, that’s worth following up on directly.
This step doesn’t take long, but it rules out a forged or expired certificate that’s been reprinted and reused, which is far cheaper than discovering the gap after a client asks you to produce proof and you can’t.
The 3 Most Common Certification Mistakes
The first mistake is treating “biodegradable” and “compostable certified” as the same thing. Biodegradable just means the material theoretically breaks down, with no standardized test verifying the speed or completeness of that breakdown. Compostable certification means it passed an actual standard’s testing.
The two aren’t interchangeable, and if a supplier only emphasizes “biodegradable” without a certificate to show, that gap is worth pressing on directly.
The second mistake is assuming certification for industrial composting carries over to home composting. ASTM D6400 and EN 13432 mainly verify conditions at industrial composting facilities, which run hotter and longer than a home compost bin. A material that breaks down at an industrial facility doesn’t automatically break down in a reasonable timeframe in a backyard compost bin.
The third mistake is getting the certificate and never checking back on it. Certifying bodies typically require periodic re-verification, and a supplier still using an expired certificate is effectively presenting old data as a current guarantee. It’s worth checking how much time is left on the certificate rather than assuming it’s valid indefinitely.
For a general framework on evaluating a supplier’s overall qualifications, see How Do You Evaluate a Food Container Supplier? 8 Questions That Apply Across Materials. Folding certification verification into that existing checklist makes it more complete.
At its core, compostability certification for plant fiber containers isn’t about whether a label is slapped on the box. The standard’s applicable region, the testing details, and the verification work once the certificate is in hand all matter.
Spending the time to confirm these upfront is far cheaper than being forced to find a new supplier after discovering the certification doesn’t match your market’s requirements.