Wait, is my compostable packaging not compostable?

Compostable and biodegradable products – including bio- and fossil-based plastics and fibre-based products (e.g. wooden cutlery) – are becoming more common as the public becomes increasingly aware of the environmental harm plastics can cause. However, compostable products aren’t a silver bullet to our plastics problem, and are widely misunderstood in Aotearoa.

Throwing your ‘home compostable’ coffee cup lid into your home compost bin may mean you find it still sitting there months later. Even with certification, compostable products may not be all that they seem. A recent study found that 60% of sampled plastic packaging items certified as ‘home compostable’ didn’t fully break down in real world home composting situations.

Even commercially compostable products aren’t straight-forward. Products that are commercially compostable are often undesirable inputs to the composting process (they add little nutrient value, could introduce contaminants to the compost, and essentially treat our soils as waste disposal pathways for single use products), and may not be suitable for anaerobic digestion. Plus, a commercially compostable product must make its way to a composting facility where it can be processed, but New Zealand currently lacks the logistics to reliably achieve this.

Further information about compostable and biodegradable products can be found in a 2018 report prepared for the Parliamentary Commissioner for the Environment, the Commerce Commission’s Environmental Claims Guidelines, the OPMCSA Rethinking Plastics report, the New Zealand Composter’s position statement on compostable packaging, the Ministry for the Environment position statement on compostable products, and a 2019 report on plastics in the environment produced by the Royal Society Te Apārangi.

Date released: 29 March 2023
Last updated: 29 March 2023