Compostable materials go a step beyond biodegradable materials by breaking down into natural components and becoming a part of healthy soil. Home compostable materials do not require the high heat (over 136° F)1 of industrial compost facilities to break down. They can biodegrade in the moderate heat (68-86° F) of home compost piles/bins. The concept of home compostability has come to carry extra weight as many commercial compost facilities are refusing to collect products designed for industrial compost8.
Tests for compostability measure material disintegration3, ensure the tested material has no adverse effects on plant growth, and account for toxicity by setting minimum amounts of heavy metals9.
Home composting certifications include TUV's OK compost HOME certification in Europe, and AS-5810 Home Compost standard6 in Australia. In the United States, BPI offers certification but only for industrially compostability.
Why choose it?
If it can meet your design needs, home compostable packaging is a better choice than industrially compostable packaging because there is a higher likelihood that the material will actually get composted — either at home or at a neighborhood dropoff.
The infrastructure is not yet in place in most US cities to properly process industrially compostable materials3. Some cities have local drop-off or compost pick-up services to meet the needs of cities that do not offer curbside compost collection4.
The purpose of composting is to return nutrients to soil and limit the amount of greenhouse gas released into the atmosphere as materials degrade in landfills. Compostable packaging is not nutrient-rich in the way that nitrogen-packed food waste or lawn trimmings are. Compostable packaging offers carbon to compost, which is a much smaller proportion.
However, compostable packaging can be particularly effective when designed in tandem with products that inherently return nutrients to the soil (i.e. containers for food waste or poly bags that double as food scrap bags)
Home compostable materials are also industrially compostable, though not all facilities accept compostable plastics8.
Why not choose it?
Some home compostable options, particularly compostable poly mailers, may not meet the long shelf-life needs of brands. On the other hand, compostable plastics take at least 12 months to break down in a home compost setting8.
Not everyone has access to composting, where as the recycling infrastructure is more robust and readily available5,6. When it comes to paper — which can recycled up to seven times — recycling can actually be a more sustainable way to sequester CO2 by extending the life of the material7.
Frequently asked questions
ASTM D6400 - 12 Standard Specification for Labeling of Plastics Designed to be Aerobically Composted in Municipal or Industrial Facilities (ASTM)
Brenda Platt, Nora Goldstein, Craig Coker, Sally Brown. State of Composting in the US (ILSR, 2014)
ASTM D6868 - 17 Standard Specification for Labeling of End Items that Incorporate Plastics and Polymers as Coatings or Additives with Paper and Other Substrates Designed to be Aerobically Composted in Municipal or Industrial Facilities (ASTM)
Packaging waste directive and standards for compostability EN 13432 (BPF)
AU Standards: Biodegradable plastics suitable for home composting (Standards Australia)
Daniel Binkoski. Mitigating Paper Emissions Through Sustainable Forestry (Lumi, 2017)
Katelan Cunningham. Ask Lumi: Is Compostable Plastic Better for the Planet? (Lumi, 2019)
Ian Montgomery. Ask Lumi: Does Soy Ink Actually Make a Difference? (Lumi, 2019)
Home Composting (Cal Recycle)
Adele Peters. Will compostable packaging ever be able to solve our waste problem? (Fast Company, 2019)