The Complete Guide to Composting Cardboard

The Complete Guide to Composting Cardboard

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One of the most used items for shipping is cardboard boxes. They have always been essential for shipping and even more so with the pandemic. More folks have been faced with more cardboard than in the past, so trying to properly dispose of it safely so that it reduces waste on the economy has been essential.

Below is the best information available regarding cardboard boxes and compost cardboard boxes properly. There is a way to keep so much of it out of the recycling facilities and break it down successfully into useable compost.

Can You Compost Cardboard? Is Cardboard Safe For Compost? What Is and Isn't?

In most cases, cardboard can be composted to avoid cardboard waste. In landfills across the country, over 30 percent of that waste alone is cardboard waste that is made up of the following:

  • Cardboard egg cartons
  • Cardboard cereal boxes
  • Cardboard Paper towel rolls
  • Cardboard toilet paper rolls
  • Shoe boxes
  • Pizza boxes
  • Plain cardboard boxes

If the cardboard is recycled back into the environment as green materials by composting cardboard, then it could reduce the waste in these landfills significantly, especially as cardboard packaging continues to be one of the leading methods for shipping items across the country.

Is Cardboard Compostable?

Most of the cardboard that ships these items can be composted, especially if they are in their natural cardboard state. Some cardboard is colored cardboard and may not be suitable for compost but can be placed in the recycling bin to be repurposed.

Is Cardboard Biodegradable?

Yes, all cardboard will start to break down because it is biodegradable. Once you start soaking cardboard, it will release the carbon and be a great benefit to compost that you are using with other organic waste.

Pairing cardboard with other high-carbon materials will allow it to release the excess moisture that the decomposition process needs in order to break down decomposed materials. Adding this to the compost with spoiled food and paper cups are just some of the ways to enhance the benefits of the cardboard, allowing it to break down.

Types of Cardboard That Can Be Composted

Since there are different types of cardboard that you can receive in your daily life, it is important to know what is compostable. Some can easily be added to an already growing compost pile with brown materials, while others need to break down a little further to be used as compost.

1. Corrugated Cardboard

The corrugated cardboard will break down the fastest of the different cardboard types. It is often used for packaging and is already ribbed in its construction. In most cases, you find this type of cardboard in packaging as a filler to keep items from breaking and as a layer in the box itself.

There are corrugated cardboard egg cartons and other things that need that durability. When you go to compost cardboard packaging made from corrugated cardboard, you may need to break it down into multiple pieces and shred cardboard. They can come in larger sheets and need the layers separated, also.

2. Flat Cardboard

Regular flat cardboard is easy to compost and will also break down pretty quickly. As long as there are no other materials mixed with this cardboard, it too will need to be broken down into strips, but otherwise, it can be added directly to the compost pile and will start breaking down.

3. Wax-Coated Cardboard

While it can be composted, wax-coated cardboard will break down, but it can take much longer than the other types to become garden waste.

In order to remove the wax from the cardboard, the cardboard would need to be submerged in water in an attempt to remove the wax from the cardboard and make it completely green materials. Unfortunately, this is not always the case, as some are so full of wax coating that they are not able to remove the wax.

At that time, it is a better option to go ahead and use the wax-coated cardboard for recycling purposes. It is easier for this type of cardboard to be recycled. In most cases, waxed cardboard is only used for one purpose: to transport raw food items.

In an attempt to prevent cross-contamination and support food safety, these boxes are not often reused. If they are not recycled or go through the grueling process to make them usable for compost, they are thrown in the landfill, where they take a long time to break down and start biodegrading with other waste materials.

What Cardboard Should Not Be Composted?

If there is one to choose from that should not be composted, it is definitely the waxed cardboard. There is a lot of work required to possibly make it an option for compost, and in the end, it still may have too many chemical and processed ingredients that keep it from being added to green materials in compost bins.

Large pieces of cardboard and intact boxes should also not be composted because they will not break down fast enough. They will absorb too much of the moisture from the rest of the compost, impacting the alternating layers that were trying to be developed and causing trouble for the compost.

Coated cardboard should not be used because of the dye and paints used in the material. This is your pet food bags and others that are colored. It is no longer natural and can have an adverse effect on the overall compost properties.

It is like the wax on some cardboard, but there is no way to get it removed. Once the paint and dye are on the box, it is completely part of the box and cardboard. Like the wax cardboard, you could take this to your local recycling stating and see if they will accept it.

Why Is Cardboard Good For Compost?

If you want to add a good carbon source to balance your nitrogen-rich materials in your compost, cardboard waste makes that happen.

Cardboard is also an organic way to start building layers in your compost. They allow air pockets to move throughout the other green materials so that there is balance when you add your compost to your plants. The cardboard will help other natural materials in the decomposition process so that the right amounts of moisture are absorbed and then released when necessary at a later time.

Most cardboard makes the compost have a different texture, which is supported by many of the plants and vegetables in your garden. Adding compost to the soil with cardboard allows the roots to spread out and keep from getting tangled with others nearby that may have been planted. Some areas may be too nitrogen-rich, but the break up with the brown materials of cardboard gives a complete balance.

How To Compost Cardboard?

Now that you have decided that your cardboard is going in your compost, it is time to determine its best methods so that it works the best for you and adds to the smelly mess you are turning periodically.

The first thing to do before you start composting your cardboard is to use your box cutter and remove any plastic tape that may be on your cardboard. This will not break down during the composting process, so you want to get rid of it before it causes issues later.

1. Shred It

With your box cutter, go ahead and shred your cardboard. It does not need to be in the large sheet that you have at home or in large chunks. You want to break it down into inches so that it will mix and blend in the compost bin. A compost bin is not usually large enough to handle sheets of cardboard or some of the other sizes of cardboard waste.

2. Don't Forget to Layer

When you add your cardboard to the composter, you want to add it in layers. You do not want it to clump up in one area of the compost and avoid the rest of the organic materials. You want it to blend but do so in a way that air pockets are able to work through the compost and create the same texture and consistency throughout.

3. Remember to Turn The Pile

Your compost bin should get turned regularly every few days to make sure that it is blended and the shredded cardboard goes through the composting process. If you do not turn the pile regularly, you will not only get a smelly mess, but you will start to have compost concentrating in certain areas. One part may be nitrogen-rich, while the other side is lacking it. That is true for all nutrients that are in the compost.

4. Try Lasagna Method Composting

If you start the compost pile with this batch of cardboard, you could try this method to build your compost. In this case, you would actually use sheets of cardboard to add layers through the compost. Based on the size of your compost heap and what you are using to store it, you want to make sure they are cut to size.

You will start your compost with sheets of cardboard and then add a layer of soil. You will wet your compost and add a top layer of cardboard with each layer.

Since there are solid layers and you are adding to the compost regularly, you do not have to go through and turn the compost. The only downside to this method is that it will take longer, but it is good for those who have the time to let it build and use sheet mulching in their gardens.

5. Use Only Clean Cardboard

You want your cardboard to be clean and free of anything when added to the compost. There does not need to be any materials on the cardboard, and there should not be anything that is not organic.

Any coating or wax cardboard should be removed from the compost and sent to recycling to avoid adding to the waste in the landfill.

How Long Does it Take For Cardboard to Decompose?

If you do nothing to your large pieces of cardboard, then it can take them naturally about six to eight months to break down completely. This is what happens when the box is thrown in a landfill or outside and is left to the elements to start breaking down. Because it is made from brown materials, it will break down, but it will take a lot longer without a helping hand.

If the cardboard has been appropriately prepped and shredded cardboard before being added to the compost, the breakdown is around two months or a little more, providing you are properly stirring the kitchen waste and organic matter that is making up your compost.

How Do You Shred Cardboard for Composting?

If you want to shred cardboard but are not sure where to start, begin with your large pieces of cardboard and start breaking them down. You can rip the cardboard, cut it with scissors if it is from large boxes. Your goal is to make small strips that you will add gradually to the other plant life in your compost.

If you have thin pieces of cardboard like toilet paper rolls or paper towel rolls, you can run them through a paper shredder to break them up and get them in the necessary small strips. You do not ever want to include synthetic substances when you add cardboard.

Can You Make Compost in a Cardboard Box?

If you have a large enough cardboard box and are interested in the lasagna method, you can easily keep your compost within the box. Continue to add different layers until you reach the top of your cardboard box.

Once the box is full, you can add the tops and close the box up or add another layer and continue building the compost. Before choosing a box, make sure that it doesn't include synthetic substances. You are able to take advantage of sheet mulching when you add in this cardboard box.

Final Thoughts On Composting Cardboard

If you have started a compost pile and want to add cardboard to it, it is an excellent addition for a number of benefits. While it takes a couple of months to break down, adding a Karfo composter will help you get the desired benefits of the cardboard in no time. Most of the waste is food waste in the Karfo, which adds to the brown materials your compost needs.

You may also want to know:
How Does Karfo Work
Why Choose Karfo Food Waste Composter

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