1. Certified to BS EN13432 (requirement for packaging recoverable through composting and biodegradation)
or meet requirements of an appropriate home composting specification.
Home compostable refers to any product that has been certified as such
(either through an independent scheme or via self assessment and compliance ISO 14021).
In general home compostable plastics would meet industrial compostable standards
(e.g. the most commonly used home composting scheme is ‘OK Compost Home’ which requires compliance with BS EN13432).
However those materials which meet EN13432 do not necessarily compost under home composting conditions.
(Whilst there are no UK or international standards for home composting (only independent, private schemes),)
Importantly, all compostable plastics are biodegradable,
but not all biodegradable plastics are compostable
Despite definitions being available in EU regulation (Dir2019/904),
the term biodegradable is also often misused and applied to a broad range of different materials.
Without a specified environment and time frame, the term is extremely vague,
because a biodegradable product may biodegrade in some environments and not (in any reasonable timeframe) in others.
Importantly, all compostable plastics are biodegradable, but not all biodegradable plastics are compostable.
Environments such as in soil, fresh or marine water are not controlled in any way,
and therefore the time for a material to?biodegrade will vary massively.
The term biodegradable is therefore best avoided as a label for plastic materials as it infers a general behaviour of the material and could mislead users to think that something will automatically biodegrade in a reasonable timeframe.
from https://wrap.org.uk/resources/guide/compostable-plastic-packaging-guidance