Not all composts are created equal
Brands are looking for materials that will make their products appear more 'green' to consumers as single-use plastics are increasingly being criticized. Due to this, there is often confusion (sometimes intentionally so) regarding terms such as compostable, biodegradable, oxo-degradable, and degradable. At the extreme end of the spectrum, this results in consumers being misled by unsubstantiated ‘green’ marketing claims.
Composting usually relies on heat as the most important ingredient. You need a lot of it when it comes to industrial composting.
The material in industrially compostable items (such as coffee cups and utensils) is usually thicker and contains more compostable material. In order to break down within a reasonable time frame (usually 90% degradation in 90 days), they require higher temperatures (around 70°C).
A few certifications are available for industrially compostable products. A few NZ-recognized international standards are shown below.
It is more difficult to become a home compost-certified product, as it has to breakdown in a natural backyard compost setting. Home compostable products are generally made from thinner materials, like our paper bags or Little Green Dog poop bags. Usually, they require 20°C to 30°C to break down, and a longer period of time to do so (usually 90% degradation in 365 days).
Although some products might be home compostable certified they should only go into composts that do not go on edible plants. An example of this is home compostable pet poop bags, they can absolutely be composted but in a compost that is separate to the one you would put on your vege garden or fruit trees.
New Zealand has a few internationally recognised composting certifications (shown in the following table).
How can you tell if a product is certified?
The short answer is: they'll be proud to show it off. You should request a copy of any certification from a company that claims to be compostable, and you should be very skeptical of companies that make claims about their eco-friendliness without being able to back them up.
Compost standards are registered, and each one has a specific registration number that corresponds with the holder of the certificate. Every product will state under which certification program it has been tested and certified.