Can We Compost Milk Cartons? How?

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Quick Answer: Can We Compost Milk Cartons?

The answer is not straightforward. Technically, we can compost paper milk cartons. However, they have a thin plastic coating that makes them difficult to decompose. You may have to tear down the plastic lining without leaving any residue to compost them. The shelf-stable cartons with aluminum coating can not be composted. So, it is best to recycle the cartons with plastic or aluminum.

This is a comprehensive guide on composting milk cartons.

Let us dive into the guide!

Can We Compost Milk Cartons?

The answer is tricky. We can not easily compost paper milk cartons as they have a thin plastic coating. It takes a long time to decompose. Also, you can not compost shelf-stable cartons coated with aluminum.

But, these cartons are sprayed with a thin layer of polyethylene (plastic) that may not decompose easily.

You may have to tear the plastic lining without leaving any residue to decompose. Also, shelf-stable cartons have aluminum that can not be composted.

The cartons with plastic and aluminum may be recycled instead of composted and disposed of properly.

Newer milk cartons with plant-based paperboard technology and renewable coating from sugarcane may be composted.

However, more research studies are required to validate them.

Check this video for more information:

Why Do Paper Milk Cartons Take A Longer Time To Decompose?

The milk cartons take time to decompose as they are coated with a thin plastic layer. It will slow down the action of microbes.

There may be a low-density polyethylene (LDPE) plastic coating that encases the paper carton. This will remove the moisture required for the decomposition process of the paper.

The microbes will not effectively degrade the coated paper.

The shelf-stable cartons have a layer of aluminum to prevent the liquid from having direct contact with the paper. These take a longer time to decompose.

So, if you see a milk carton in the compost that has not decomposed, it may be because of the polyethylene and aluminum protection. It is preferable to remove them from compost.

What Are The Problems With Composting Plastic-coated Cartons?

The plastic-coated milk cartons may produce macro and micro fragments when added to the compost pile. These non-biodegradable fragments may contaminate the finished compost.

The degraded plastics may not add any nutrients to the soil. They may pollute the land and water sources if dispersed into the environment.

They may be difficult to clean up as they get dispersed widely. They may affect marine life and humans.

Can You Recycle Milk Cartons?

Yes, you may recycle them if you can not compost them. But, they require industrial recycling centers. You may recycle them in the plants that may specialize in separating carboards from polyethylene and aluminum.

They use the paper pulping process that may extract the paper fiber. You need not rinse the cartons before recycling.

The cartons are shredded and applied heat to press them. The separated pulp is rolled into sheets and turned into new products.

Can You Compost Bioplastics?

Yes, We can compost bioplastics but they require industrial composting. The industrial composters may heat the bioplastic to a high temperature that allows the microbes to break down.

These bioplastics may not degrade on their own or in a home compost heap as it requires a very high temperature.

So, they can be composed only in an industrial setting.

They may end up in landfills and take a longer time to decompose. They may pose a threat to marine life.


What are the different types of milk cartons?

There are gable-top and aseptic cartons. The gable top, also known as the refrigerated type is made of about 80% paper and 20% polyethylene. The aseptic or shelf-stable cartons are made of 74% paper, 22% polyethylene, and 4% aluminum.

What to do with used milk cartons?

One of the popular things to do out of used milk cartons is to create a planter box. You may use it as floor protectors while moving, a birdhouse, collars to prevent bugs, organizers, and a plant mixer.

How to compost paperboard milk cartons without plastic?

Shred the paperboard cartons. Layer it with high carbon materials. Alternate with high nitrogen materials, including grass clippings. Add some soil on top and continue to layer till the pile is four cubic feet. Turn the compost occasionally to speed up the process.

Bottom Line

I hope this guide has helped you with certain considerations on composting milk cartons.

Do you have experience in composting milk cartons? If yes, please let us know your results.

Share this with your friends and family who love composting.