Plastic Waste Hub
Organic material and dry leaves in a home compost container

Completed citizen-science project

The Big Compost Experiment

A UK-wide study of attitudes to home-compostable plastics and how labelled packaging performed in domestic composting conditions.

  • Home composting
  • Citizen science
  • 2019–2023
Garden compost being inspected among green plants

Project overview

Testing labels against real conditions.

The Big Compost Experiment was a four-year citizen-science project examining public opinions and behaviour around home-compostable plastics. It also investigated how examples of this packaging performed in home composters across the UK.

The study ran from November 2019 to August 2023. It formed part of a wider research initiative on compostable plastics and the barriers that influence effective systems change.

The project is complete. Its value lies in showing why disposal claims need to be considered alongside household behaviour, variable composting environments and clear instructions.

Read the published resultsRelated project

What the study considered

Compostability is a system claim.

A label describes an intended treatment route, but successful breakdown also depends on the item, the compost environment and how people understand the instructions.

Household understanding

The project examined how people interpreted compostability claims and decided which packaging to place in a home composter.

Variable conditions

Domestic compost systems differ in temperature, moisture, aeration, contents and maintenance, so they do not offer uniform treatment conditions.

Observed performance

Participants helped document what happened to selected packaging over time, connecting material claims with use in everyday settings.

How the project worked

From household choices to research evidence.

Citizen participation made it possible to explore behaviour and material performance across a range of domestic composting situations.

Understand attitudes

Gather information about familiarity with compostable packaging, disposal choices and home-composting habits.

Run home trials

Place eligible test items within participants’ existing compost systems under ordinary household conditions.

Record outcomes

Observe and document how items changed over time rather than assuming a label guaranteed the same result everywhere.

Analyse context

Relate reported outcomes to packaging identification, user instructions and the variability of home composters.

Why it matters

A material needs the right route.

Compostable packaging is not designed to become litter and should not automatically enter conventional plastic recycling. Its practical value depends on an appropriate application, recognisable labelling, informed disposal and a compatible treatment process.

The experiment helps place product claims in this wider context. It also demonstrates why evidence from real use can complement controlled material testing.

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Rich finished compost held above a garden bed

Common questions

Reading the experiment carefully.

Was The Big Compost Experiment a laboratory trial?

No. It was a citizen-science project focused on domestic composting situations across the UK. Those environments are naturally more variable than controlled industrial or laboratory conditions.

When did the project run?

The project ran from November 2019 to August 2023 and is now complete.

Does “compostable” always mean home compostable?

No. Some products are intended for industrial composting, where managed conditions differ from those in a garden composter. The applicable certification and disposal instructions need to be checked.

Will home-compostable packaging break down in any environment?

No. Compostability does not mean an item will quickly break down in soil, water, roadside litter or every home composter. Conditions and timescales matter.

Can compostable plastic go into plastic recycling?

It should not be assumed to belong in conventional plastic recycling. Follow the collection guidance for the specific item and local system.

Where can I read the published results?

A link to the published research appears in the project overview above. The paper provides the methods, analysis and limitations needed to interpret the work.

Get in touch

Ask about the project or suggest a correction.

For questions about this archive summary or to flag supporting material, email Plastic Waste Hub and include the project title in your message.