What’s the real definition of compostable?

What’s the real definition of compostable?
10 Minute Read

Have you ever seen those products that have the word ‘compostable’ written on them, like disposable forks, knives, or food containers? These commercially compostable products often look and feel like plastic, but are actually made from plants. Now, getting away from plastic is great, but here’s the problem: even though those products are technically compostable, they don’t actually biodegrade naturally. They won’t break down in a landfill either.

This is the point where everyone gets a little confused. You probably think the definition of compostable means that it can naturally break down or biodegrade. However, when it comes to compostable plastics, this just isn’t the case. At the end of the day, they’re great, but due to the lack of education around them, they’re not as harmless as you think they are. And with compostable plastics replacing many of the single-use plastics on the market, especially in the food industry, I wanna clear up any confusion you may have around them.


Here’s the REAL definition of compostable:

Compostable products are made from renewable resources such as corn, bamboo, and sugar cane. Whenever you see a product with the word ‘compostable’ on it, what that really means is it’s commercially compostable. A commercial compost facility is a place where the perfect balance of heat, moisture, and oxygen is created to break down organic and plant-based materials. Without this perfect ecosystem, compostable products don’t break down. To really put that into perspective, if you dispose of them in the trash, which is what people commonly do, they won’t break down.

For a product to be labelled as compostable, the materials must disintegrate by 90% within 90 days of being in a commercial facility (WorldCentric.org). In addition, they must create zero toxicity during the degradation process. If they don’t meet these requirements, they can’t be certified as compostable.

Image of a hand holding a disposable utensil


Biodegradable VS Commercially Compostable, and the Element of Greenwashing:

Here’s where I get a little sciencey: “The term biodegradable is … often misused in [the] marketing and advertising of products and materials that are not actually environmentally friendly… The definition of biodegradable is a material [that] is capable of undergoing biological … degradation, leading to the production of [carbon dioxide, water,] methane, biomass, and mineral salts… [However, unlike something that is certified compostable], the term biodegradable means very little, as everything is biodegradable [over time]” (BioBag). In other words, something can take 5,000 years to naturally biodegrade, and legally, it can still be labelled as biodegradable.

Greenwashing can be a very effective marketing strategy. It’s used to create the illusion that a company or organization has taken environmental factors into consideration when creating their products or services. It’s important to watch out for products that are labeled as biodegradable because you are likely being greenwashed. Unless a product states the length of time it will take to biodegrade, for example, three months, it does not fit into the definition of compostable.

Keeping all of this newfound information in mind, it’s important to note that compostable products don’t solve the world’s pollution problems. Without proper disposal, they’re as much of a threat to our oceans and wildlife as regular plastics because they don’t break down in nature.

My guess is you probably still have a ton of unanswered questions about commercially compostable products. To help you out, I’ve put together this list of FAQs to explain the common ways of identifying them and what proper disposal looks like.

Understanding the True Definition of Compostable

Commercially Compostable Products: Let’s Break it Down [pun intended]


What’s the difference between regular plastics and compostable plastics?

There are two main differences:

  1. Compostable plastics are made from renewable resources, such as corn and sugar cane, while traditional plastics are made from nonrenewable resources such as oil, gas, and coal.
  2. Compostable plastics are non-toxic, while regular plastics leach toxic chemicals into our bodies and into the environment. “Exposure to [these chemicals has been] linked to cancer, birth defects, impaired immunity, endocrine disruption and other ailments” (Plastic Pollution Coalition).

To summarize, compostable plastics are non-toxic and come from renewable resources—both good things for us and for the environment. However, they are not the solution to pollution and disposal issues. Because they fall into a new category that 99% of people have not been educated about, they often end up sitting in a landfill, or worse yet, finding their way into our waterways and oceans. Remember the video with the turtle and the straw? That could just as easily have been a compostable straw.


How do I know if something is true to the definition of compostable or not?

It will have:

  1. The word ‘Compostable’ written on it
  2. The letters ‘PLA’ written on it, or
  3. A recycling arrow with a #7 printed on it**

Image of a number 7 in a recycling arrow, which is used to identify compostable products

**Important: If a product has a #7 inside of the recycling arrow printed on it, but does not have ‘compostable’ or ‘PLA’ on it, then it is NOT compostable. The #7 is also the label for mixed plastics, which are neither recyclable nor compostable. I wish there was a better labelling system, but that’s the way it is right now. Any U.S. legislators reading?


Image of a hand holding a disposable utensil


So, how do you dispose of compostable products?

The best way is to send them to a commercial compost. Many cities or towns will provide bins to local organizations, parks and residents to facilitate proper disposal. If a compostable product has more of a paper consistency, or is a very thin film, it can potentially be disposed of in a backyard compost. This is not guaranteed, however, since decomposition relies on the elements (heat, moisture, oxygen).

**A backyard compost is a small-scale compost that uses natural elements and manual turning to aerate and break down organic materials. Commercial composts, on the other hand, have the ability to break down more dense materials (such as large branches and compostable plastics) that cannot be broken down quickly. For more information on the difference between backyard and commercial composts, click here.


Can compostable products be put in commercial compost bins along with food scraps?

Yes. Compostable products are made from plant byproducts, so they need to be disposed of in a commercial compost bin. Other accepted organics include food scraps, yard trimmings, dairy, meat, hair, nail clippings [you asked, so I’m getting real specific here], etc. For a full list of accepted items, click here.


Will commercially compostable plastics biodegrade in the trash? 

No. If sent to the landfill, compostable plastics can take as long as regular plastics to degrade or break down. Landfills simply do not have the oxygen and ventilation required for decomposition.


Can compostable plastics be put in the plastic recycling bin?

This is a hard NO. Because compostable plastics are made with different materials, they contaminate the recycling process.

Image of a hand holding a disposable utensil


How long do compostable products need to be gone?

Compostable products take 90 days to break down in a commercial compost facility. This is because the commercial environment is carefully controlled and regulated to facilitate optimal degradation. So, what about outside of a facility? Well, there is simply no way to tell how long they will take to break down. The time frame will differ based on the environment and climate. Usually, these conditions are not regulated in the same way that they would be in a commercial setting. In other words, it could take hundreds of years (i.e. just as long as standard plastic).


Why are they labeled as compostable if we can’t compost them at home?

As mentioned above, in terms of product labeling, the term ‘compostable’ always refers to something that is ‘commercially compostable.’ Presumably, they axed the ‘commercial’ part to simplify the label. However, without proper education, consumers are unaware that the products are not naturally compostable or biodegradable.

I think the responsibility lies with the manufacturers of the products as well as local governments. Both entities should be responsible for educating the general public about proper disposal. In addition, perhaps adding labels such as “not naturally biodegradable” or “suitable for commercial composts only” could bridge the educational gap.

Let’s look at an analogy. If the government redefines what jay-walking is, and doesn’t educate the general population of the new regulations, how can they expect you to abide by the law? Likewise, if you’re not educated about commercially compostable products, how can you be expected to responsibly dispose of them?


Are there any compostable products that biodegrade naturally or quickly?

Compostable packing peanuts can easily break down within a few seconds of being exposed to moisture. If you submerge compostable packing peanuts in water, they’ll quickly disintegrate into a slime or sludge. In addition, paper-like products, such as compostable paper straws, can biodegrade in a backyard compost or compost tumbler. Depending on the environment, the straws will likely take a few weeks/months to biodegrade.


Image of paper straws

compostable paper straws


Is it better to use commercially compostable bags instead of plastic bags?

Compostable bags are made from renewable resources, and they don’t have the same toxins and chemicals as plastic bags. For these reasons, it is my personal conclusion that they are a better alternative to plastic bags. That said, they typically do not break down in a landfill, just like plastic.


Other than compostable products, what can I put in a commercial compost?

The New York City commercial compost bins accept the following common household items. Keep in mind that each city differs, so its best to check with your local facilities.


  • Cooked, baked, and otherwise prepared foods
  • Cereal, flour, grains, pasta, and rice
  • Spoiled and expired food
  • Eggs and eggshells
  • Dairy products
  • Meat, fish, bones, seafood shells
  • Nuts, seeds, pits, and shells
  • Coffee grounds and tea leaves
  • Pet food

Food-soiled Paper (Uncoated):

  • Towels and napkins
  • Paper plates
  • Coffee filters and tea bags
  • Paper bags
  • Uncoated food service paper trays and boxes
  • Any other food-soiled paper

Leaf and Yard Waste:

  • Leaves
  • Grass clippings
  • Garden trimmings
  • Plants and flowers
  • Potting soil
  • Branches
This was taken from the New York City Department of Sanitation Website.


Is animal waste (aka dog poop) accepted in commercial compost facilities?

Sadly, no. I made an inquiry with the NYC Department of Sanitation (DSNY). They said that their processors are unable to accept animal waste “while ensuring the finished compost is free of excess salts or pathogens. Municipalities that claim they accept pet waste in their organics program typically do not actually compost the material, but instead opt to send the material to an anaerobic digester. During this process, bags, both plastic and compostable, are removed and sent to landfill as residual waste” (Bureau of Recycling and Sustainability, NYC Department of Sanitation).

This means that those Compostable Poop Bags that you use to clean up after your pooch should be disposed of in the trash, not the compost. I’m sorry to be the Debbie Downer here.


What about bamboo products? Will they break down in a backyard compost?

Since bamboo is an organic material, a bamboo toothbrush can take about six months to break down in a backyard compost (this is an estimate for Brush with Bamboo toothbrushes; other brands may vary). NOTE: the majority of bamboo toothbrushes have plastic/nylon bristles. These are neither biodegradable nor compostable. These bristles must be removed from the bamboo handle, which can easily be done with pliers. Some bamboo toothbrush companies are starting to use plant-based bristles, which are less reliant on fossil fuels. But these are still compostable plastics and will not biodegrade outside of a commercial compost facility.


Image of three bamboo toothbrushes, a compostable alternative to plastic toothbrushes


Conclusion: How to understand the real definition of compostable:

Because most people don’t understand the real definition of compostable (due to lack of education around it), consumers often believe they’re making an environmentally friendly decision (compared to using plastic). In reality, they are not making the best choice because they’re not disposing of these items in a commercial compost. This is because they’re uninformed about proper disposal or don’t have access a commercial compost facility.

In the future, I see a world where commercially compostable products replace regular plastics across all industries. But consumers need education about proper disposal. In addition, commercial composts need integration into our waste disposal systems. In the same way that landfills are today. Every district, city, and town should have a commercial compost, paralleled with curbside collection so that it is easy and accessible for everyone. This will lead to a significant decrease in the size of landfills across the globe, reducing land toxicity levels, air pollution, and climate change.

I can’t stress the importance of doing your research on the products that you use. Don’t assume anything is recyclable or compostable without first verifying via the packaging, labeling, or company website.

I’m always here if you have follow up questions about the definition of compostable. Or if you wanna know more about compostable products in general. Just drop me a line below 🙂


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13 thoughts on “What’s the real definition of compostable?”

  • I am moving to a location where burn bins are an acceptable, even encouraged method of disposing of paper waste, I e. Pizza (even greasy), cereal, and shipping boxes & food scraps, etc. Obviously the question is are commercially compostible products safely burnable?

    • Hi Scott, to be honest, I’m not sure the answer to your question. I will need to do some more research on the practice of burning paper-based items before giving you an educated answer.

    • As a qualified graduate paper technologist I feel I have the authority to respond.
      Burning paper should be regarded as a no no and actively discouraged. It releases the carbon back into the atmosphere as carbon dioxide. Likewise the burning of any organic material like food or garden waste should be discouraged as it will contribute to greenhouse gases. Paper is a material of natural and sustainable origin and has been recycled for decades. Most cardboard packaging is made from recycled paper. Modern paper and board recycling operations cope with the multitude of contaminants (food waste, packaging adhesives, plastic coatings. Food waste should be composted and returned to the soil as fertiliser.

      • Totally agree. A few years ago when Greece was going thru a major financial crisis, many Greeks resorted to burning wood in order to save money for heat. This resulted in major air pollution crisis; a lot of bad things are released into the air from burning wood/paper. https://phys.org/news/2012-12-wood-burning-pollution-alarm-bells-athens.html

        Excerpt from Above Link:

        ” “The smog, which appears especially in the evening, is made up of polluting and dangerous particles that can cause respiratory problems,” said Evangelos Gerassopoulos, director of the Environment Institute of the Athens Observatory.

        “This polluting cloud is the result of the combination of a lack of wind and the burning of wood, which is more prevalent than usual because of the high price of domestic heating fuel,” Gerassopoulos told AFP.”

  • I think too much emphasis is placed on biodegradable/compostable as it relates to the time factor. There are many things I compost (I compost 100% of my food waste, as well as my yard waste) that take much longer than 90-days to compost. Some example are eggshells, bones, pizza boxes, sticks and various seed pods…

    My only concern is if it’s toxic to the environment.

  • Question regarding commercially-compostable bags. We have a home composting bin in our bag, and we gather our scraps in commercially-compostable bags. Can I put those bags into my recycling bin, or should I empty the bag into the bin and dispose of the bag? If I do put those bags into the compost bin, will they eventually break down?

    • Hey Stephen, the commercially compostable bags *should* break down in your home compost since they are very thin, but I would recommend tearing them up or cutting them into small pieces so that they have a better chance of breaking down. Just experiment with it and see how it goes. If they break down after a few months, then you’re good to go. If they don’t, perhaps your compost isn’t getting super hot, and then it might be best to dispose of them in the regular trash. Don’t put them in the recycling bin as they will contaminate the recyclables for a few reasons: (1) thin film bags cannot be recycled in regular recycling bins, but instead have to go to a specific recycling bins only for plastic bags; (2) compostable items cannot be put in any recycling bin because it’s made from a different material as plastic so it will contaminate and complicate the entire recycling process. I know that was a lot I threw at you but wanted to make sure you have all the info you need to make the most informed decision.

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