Why the confusion matters
In 2024, the UK's Advertising Standards Authority banned several brands from using the word biodegradable on plastic packaging — because the claim was technically true but practically meaningless. The item would biodegrade, eventually, under conditions that do not exist in any real-world disposal stream.
What biodegradable actually means
Biodegradable simply means that a material will break down through biological processes rather than persisting indefinitely like conventional plastic. But the word comes with no time frame, no temperature conditions, and no requirements about the end products of degradation.
A material that takes 500 years to biodegrade in a very specific soil chemistry is technically biodegradable. In practice, biodegradable on packaging is often a meaningless claim unless it comes with a certification and specific conditions.
What compostable actually means
Compostable is a subset of biodegradable with much stricter requirements. To be certified compostable, a material must: disintegrate by at least 90% within 12 weeks, biodegrade by at least 90% within 180 days, leave no toxic residues or heavy metals above set thresholds, and produce compost that supports plant growth.
Industrial vs home compostable
Industrially compostable (certified to EN 13432 or ASTM D6400): requires the high temperatures (55-60C) of a commercial composting facility. These products will NOT compost properly in a home compost bin.
Home compostable (certified to TUV Austria OK compost HOME): designed to break down at the lower temperatures of a domestic compost heap (20-30C). These can go in your garden compost bin.
The Seedling logo certifies industrial compostability. The same logo with a small house icon certifies home compostability. These are different certifications and cannot be substituted.
The problem with biodegradable plastic
Oxo-degradable plastic is a conventional plastic with additives that cause it to fragment into small pieces when exposed to UV light or heat. The fragments are microplastics — not biodegradation. Multiple countries and the EU have moved to restrict or ban oxo-degradable plastic.
What this means for your purchasing
- Ignore biodegradable without certification — it is a marketing term
- Compostable is only meaningful with a certification logo (Seedling, BPI, TUV Austria)
- Check whether the certification is industrial or home compostable
The packaging worth choosing
- Reusable packaging (glass jar, metal tin, cloth bag)
- Recyclable packaging with high actual recycling rates (aluminium, glass)
- Home-compostable certified packaging (if you compost)
- Industrially compostable certified packaging (if you have food waste collection)
- Certified biodegradable (EN 13432 or ASTM D6400)
