PLA is compostable but only in an industrial composting plant.
Under these industrial composting conditions, PLA can be biologically degraded within a few days, up to a few months. The temperatures must be above 55-70ºC. PLA can only be biologically degraded under industrial composting conditions.
Unfortunately, the term biodegradable used by manufacturers and distributors can be somewhat misleading for the final consumer when it is not further defined. The Federal Environment Agency also notes in its report that increased environmental impacts from micro-plastics can occur if more plastics are disposed of in the environment due to this communicated biodegradability.
In the wild, it takes at least 80 years for PLA to decompose, which means that in the sea and on land it contributes not only to conventional petroleum-based plastics but also to environmental pollution from plastics and above all microplastics. For this reason, PLA should not be thrown into nature, into home composters or into organic waste, just like other plastics. This leads us to the question of what happens to the PLA as soon as we throw it away.