Is Cardboard Biodegradable - Or is it Best to Recycle It?

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Cardboard is one of the most widely used materials in the world. It's strong, versatile, and relatively inexpensive, which is why it's often used for packaging.

But what happens to all those cardboard boxes when they get thrown away? Is cardboard biodegradable, compostable, or both?

Many people assume that because paper products come from a natural source, they must be biodegradable. The good news is that on this occasion, that is correct.

Yes - cardboard IS biodegradable.

But just because we can, doesn't mean we should! There are good reasons why composting cardboard might not be the most environmentally friendly option.

Read on to find out whether cardboard belongs in your recycling bin or your compost pile.

What is Cardboard Made Of?

These days, cardboard is made of around 60% recycled material. It's actually cheaper to recycle paper and cardboard than to cut down new trees - which is obviously good news.

Cardboard recycling plants also use less energy and far fewer chemicals than making new cardboard from scratch.

The manufacturing process starts by shredding old newspapers and magazines into very small pieces. These pieces are then mixed with water and chemicals to create a slurry, which is then poured onto a moving screen.

The screen separates the smaller pieces of paper from the larger ones, and the smaller pieces are collected and formed into a new sheet of paper.

This new sheet is then dried and pressed to remove any remaining water. Once the sheet is dry, it can be cut and formed into the cardboard.

Why is Cardboard Biodegradable?

Cardboard is biodegradable because it is made of natural materials. Paper is made of cellulose, a natural substance that can be broken down by bacteria and other microorganisms.

When cardboard is placed in a landfill, the paper will slowly break down and decompose.

But here's the bad news. The process of breaking down cellulose produces methane, which is a potent greenhouse gas that is more harmful than carbon dioxide.

That's why it's important to recycle cardboard whenever possible – recycling prevents methane gas from being released into the atmosphere.

Does Cardboard Decompose Naturally?

Cardboard does decompose naturally, but the process can be slow.

Over time, natural microorganisms will break down cardboard fibers fully, and return them to the soil.

How long does it take for cardboard to decompose?

The time it takes for cardboard to decompose depends on the type of cardboard, its condition at the start, the amount of moisture present, and the temperature.

Untreated cardboard such as sustainable packaging and cereal boxes will break down entirely, and more quickly, than waxed cardboard packaging such as milk or fruit juice cartons. The process can take as little as one month.

For cardboard that has a wax or plastic lining, decomposition happens much more slowly, and can take as long as 5 years.

If a cardboard box does contain this type of lining, then the lining itself will take far longer to decompose.

Cardboard that is placed in a compost bin will decompose more quickly because the compost bin will provide the bacteria and moisture that is needed for the decomposition process.

Wet cardboard that has been shredded or torn into strips will decompose faster in your compost bin.

Is Cardboard Biodegradable in Water?

Cardboard is not biodegradable in water. The cellulose fibers that make up cardboard will not break down in water.

However, if cardboard is placed in a compost bin, the bacteria and moisture present will break down the cellulose fibers and the cardboard will decompose.

Is Corrugated Cardboard Biodegradable?

Corrugated cardboard is biodegradable.

The corrugated (or wavy) layer that is added to the cardboard in corrugated boxes is made of paper, and the paper is made of cellulose, which is a natural material that bacteria and other microorganisms can break down.

Is Cardboard Compostable?

Cardboard is compostable. But it is not recommended to compost cardboard boxes in your home compost bin alongside your other organic materials. Remember the methane that is produced when it biodegrades?

Some types of cardboard don't compost though - for example, any plastic-lined cardboard packaging material will not biodegrade or compost.

But even if you have cardboard materials that are compostable, it is far better to recycle them instead.

Is cardboard good for your soil?

Cardboard that hasn't been treated with wax, glue or chemicals is very good for the soil because it is made from entirely biodegradable materials.

Composting cardboard products gives you a natural fertilizer that helps to aerate the soil and improve drainage. Cardboard also adds nutrients organic matter to the soil, which helps to improve the soil's structure.

In addition, cardboard can help to suppress weeds and keep the soil moist.

Is Cardboard Recyclable?

Cardboard is recyclable, and recycling cardboard is a good way to reduce the amount of methane gas that is produced when the cellulose fibers in cardboard decompose.

Americans recycle around 63% of waste paper and cardboard every year.

When cardboard is recycled, it is broken down and reformed into new cardboard.

The cardboard recycling process uses less energy than the process of making new cardboard from scratch.

That's why recycling is considered to be an eco-friendly way to dispose of cardboard.

However, it is important to note that paper and cardboard cannot be recycled indefinitely. Eventually, the natural pulp fibers will become too weak and can no longer be reconstituted into new products.

Also, not all types of cardboard can be recycled, Pizza boxes, for example, are not suitable because the grease and food residue on them make the material unsuitable for the recycling process.

Can you recycle cardboard with tape on it?

Plastic-based tape is generally not recyclable. If you have cardboard that has been taped on it will probably not be recycled or compostable.

However, cardboard pieces and paper can be recycled. The cardboard gets soaked in water at the recycling facilities to transform it into a liquid mix.

Usually, when this happens, the tape is easily cut out for collection from machinery or workers.

The problem is that slurry residue can reduce the final product. When possible, remove as much of the tape as possible after recycling the cartons. It applies to gift wrapping as well.

Does cardboard contain glue?

Yes, cardboard can contain glue. The type of glue that is used will depend on the type of cardboard that is being made.

There are two types of glues that are commonly used in cardboard production: hot-melt adhesives and water-based adhesives.

Hot-melt adhesives are made of thermoplastic polymers, and these adhesives are melted and applied to the cardboard.

Water-based adhesives are made of acrylics or latex, and these adhesives are dissolved in water and applied to the cardboard.

Both types of adhesives can be harmful to the environment if they are not disposed of properly.

Is Cardboard Eco-Friendly?

Cardboard is considered to be an eco-friendly material because it is renewable, recyclable, and compostable.

When cardboard is recycled, it can be made into new cardboard, and when it is composted, it breaks down and becomes food for plants.

Cardboard is made from cellulose, which is a natural material that bacteria and other microorganisms can break down. However, the process does release methane, which means that recycling used cardboard is

That's why cardboard is a good choice for packaging and shipping materials. It is environmentally friendly and can be recycled or composted when it is no longer needed.

Advantages of Cardboard for the Environment

  • Most environmentalists would consider cardboard environmentally friendly.
  • It is made from natural materials, and can easily be recycled.
  • It is both biodegradable and compostable.
  • When cardboard is recycled, it can be made into new cardboard, and when it is composted, it breaks down and becomes food for plants.

Disadvantages of Cardboard for the Environment

  • Cardboard and paper cannot be recycled indefinitely. So recycling cardboard reduces the need for trees to be cut down, but does not eliminate it.
  • If not disposed of properly, the adhesives used in cardboard production can be harmful to the environment.
  • Some types of cardboard take a long time to break down, and it releases methane when it biodegrades.
  • Cardboard is not as strong as some other packaging materials, so it may not be able to protect your items as well.

The Final Word

Cardboard is a versatile and eco-friendly material that can be recycled or composted when it is no longer needed.

In addition, cardboard is strong enough to protect your items during shipping, and it takes up less space in your compost bin than other materials.

If you are looking for an eco-friendly packaging option, cardboard is a good choice. Just be sure to dispose of it properly when you are done with it.

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Arabella Ruiz is a senior researcher at The Roundup. She lives in San Antonio, Texas and has been interested in the environment from an early age. Arabella loves to campaign for environmental causes and fundraise for charities that aim to preserve wildlife habitat, protect endangered species or help people with climate change problems.
Arabella Ruiz
Arabella Ruiz is a senior researcher at The Roundup. She lives in San Antonio, Texas and has been interested in the environment from an early age. Arabella loves to campaign for environmental causes and fundraise for charities that aim to preserve wildlife habitat, protect endangered species or help people with climate change problems.

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