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Can You Compost Cardboard?

Cardboard is one of the most used commodities in America. Think of the many things you buy daily and are packaged with cardboard. With cardboard being so prevalent, have you ever wondered if there’s a good way of disposing it?

Can you compost cardboard? Composting cardboard is possible and is recommended because cardboard is a remarkable source of carbon. Both recycling and composting cardboard are great ways to contribute to the health of the environment

Cardboard is one of the materials that not many people believe can be converted into a valuable form of compost for healthy, organic farming. However, there are dozens of benefits that come from using cardboard for composting, as you will see below. 

How to Compost Cardboard

If done correctly. Cardboard composting can be incredibly beneficial, and it is not challenging at all. If you set your compost pile correctly, you should be able to reap the benefits of using cardboard for composting soon enough.

Set aside compostable cardboard

Ensure that the cardboard you put in your pile is clean to avoid contaminating the compost and poisoning the microbes. Cardboard that has come into contact with synthetic substances, chemical spills, bleaches, and other poisons should not be placed into the pile.

Also, avoid overly processed cardboard, as this may not have any nutritive benefits left to offer your garden. Cardboard that is also lined finely with films of plastic and foils should also not be used.

Here are some types of cardboard that you can compost.

Egg cartons

Most people love having eggs for breakfast, not to mention how many fun recipes require at least two eggs. You must have dozens of egg cartons in your kitchen, and yes, you may use them to make compost. 

If your egg cartons are made of 100% paper pulp, they are fully biodegradable and thus capable of making some great compost. Squash them up, shred them, and toss them into your compost bin. If you are having a problem with too much moisture, these cartons can come in handy for absorbing the additional water. Other boxes found in the kitchen that you can toss into your garden include toilet paper and kitchen paper towel rolls and milk and cereal boxes.

Amazon boxes

If you regularly order from Amazon, you probably have a steady supply of boxes coming your way. However, you may wonder, are the inks used to label the boxes toxic for compost? Or will the paper tape on the boxes decompose? 

These questions are valid, considering the fact that cardboard takes longer to decompose than other brown material even in an active compost pile. You do not have to worry about the inks as thanks to its commitment to sustainable practices. Amazon no longer uses inks with a petroleum or heavy metal base. The ink they use to make their black logo is soy-based, making it perfectly safe to add to your pile.

The tape on the boxes also happens to be 100% compostable, though it will take a while for them to degrade quickly. The paper fiber will take a short while, while the rigid material may still show up after months. If you decide to place the cardboard with the tapes into your bin, then be ready to pull them out of the murk before you add it into your garden.  

Shred your cardboard

You are advised never to place your cardboard in entire masses into your compost bin or pile. These will take infinitely longer to decompose at all, as the microbes will have too much surface area to volume ratio to handle.

Larger masses of cardboard will also make the pile impossible to turn and adequately aerate when they clump together in one huge mass. Instead, cut them into smaller pieces, or even shred them to the smallest size possible.

When dealing with microbes, the smaller is often better. If you can sprinkle the pieces with some liquid detergent, even better, as the decomposition process will be hastened. Smaller pieces will also allow the formation of air pockets.

How to shred your cardboard for composting:

Remove plastics

First, remove all forms of plastic on the cartons, including tapes, bubble wrap, and other forms of wrapping you may have used to label the boxes or protect what was inside them. In case you are using Amazon boxes, you can leave the tapes behind, so long as you are careful to find and remove them in case of incomplete decomposition. You also want to remove pins and staples. 

Flatten and shred

Flatten the cardboard out and use a pair of scissors or box cutter to shred it into fine strips. Attempting to remove plastics and tape from shredded cardboard will be far harder, so remove them before you begin to cut. 

Moisten difficult to cut cardboard

You can try moistening the cardboard first to make cutting it easier if you do not have a heavy-duty shredder at home, or even cutting along the corrugations. If you have a lot of cardboard, place it in your tub or and cover it in water. Instead of using water, you can leave the cardboard out in the rain to soak and begin to decompose.

Set up your compost pile

Depending on the amount of shredded cardboard you have, starting a new pile to incorporate the entire mass may be more practical. If you have only a few boxes, you are allowed to add them into an existing compost pile, so long as you pay attention to the green: brown ratio. 

Start your compost pile with a 6-inch layer of shredded cardboard, plus any other source of brown organic matter such as hay, dead leaves, or straw. From there, add a 2-inch layer of nitrogen-rich greens such as kitchen food scraps, avocado, and other fruit and vegetable peels, fresh grass clippings or weeds. After this, top it all off with a 2-inch layer of soil to protect the pile and introduce microbes to the pile.

Ensure your pile has sufficient water

Water is important to sustain the microbes and the reactions needed to decompose your cardboard. The right amount of water for a compost pile with cardboard is that of a wrung-out sponge.

You may be able to tell if your pile is too dry by its appearance and feel. Your pile should resemble slightly damp earth, not dust; if it looks like the latter, you should add some water. If you squeeze a bunch of material from the pile, it should release a little water and not come apart. 

In case you find that you need to keep adding water to your compost pile, consider moving it to a place that is less exposed to sunlight.

Also, consider watering your new pile evenly to moisten it and offset some of the top layers to avail water to the bottom ones.

You can also add more green materials, especially fresh grass and other plant materials, to boost the quantity of water. Also, ensure that you placed the right amount of cardboard in your pile as cardboard absorbs water.

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Again, too much water is not good. The last thing you want is to drown your organic material in water, not to mention the fact that water displaces the oxygen that the microbes need to function.

If you feel the pungent smell of ammonia in your pile or any sample you collect feels matted, your pile is drowning. 

You can reduce the amount of water in it by aerating your compost pile. You can spin the barrel or use a pitchfork to turn the material, in case you are using a pit. Adding more shredded cardboard or other brown material will also help to absorb the water. Moving the bin to a place with additional sunlight should also help with eliminating the excessive moisture. 

Try the lasagna method

This approach of gardening is another option that you can use to compost your cardboard so that you reduce the hassle of shredding huge pieces of cardboard. You simply lay the sheets of cardboard into your garden, after which you bury them under the soil and vegetative matter, you then add layers of green materials and top up with carbon-rich browns. 

You can also layer these materials (cardboard, green, then brown waste) together to create a compost heap, only ensuring you add some water to each layer as you proceed. Over the top layer, sprinkle some soil to speed up the process by introducing additional bacteria. 

The cardboard “lasagna” will break down over a few months (3-6 months maximum), over which you can use to set up your garden and get all the flowers or plants you would like to plant. With this method, you do not even have to remove the plastic; you will get it all off when the compost is ready. 

Consider Using High Fiber Composting

The high fiber method of composting cardboard was introduced to make composting possible for people depending on the types of compostable waste they had. If you have a small yard and do not have access to dry leaves, old hay, and other forms of brown waste, then the high fiber composting is a great option for you. 

It also lets you compost your kitchen scraps to avoid the stress associated with disposing of them. If your home generates huge volumes of food waste, you may be contending with unpleasant smells in your house, and even placing it in your compost bins may be doing nothing but attract fruit flies. Since it is quite moist, adding cardboard still helps you absorb some of the moisture in your waste and facilitate air circulation. 

Using a Cardboard Box as a Compost Bin

Another interesting approach to using cardboard in composting is using it as a container for your organic material rather than part of what will be decomposed. Cardboard is an excellent candidate for a composting bin; it will decompose with time, thus providing carbon for your pile as well, is an insulator, and will thus keep heat inside your pile to accelerate the process of decomposition, and is environment-friendly. 

It may not be suitable for holding massive piles and will break down due to the moisture, but it can be a great way to get started. First off, it is free of charge, as you probably have it lying in your attic somewhere, completely empty. Unlike tumblers and plastic bins, or digging a bin, you will not incur any additional costs, nor break your back. Composting is loved for being a natural process that you should not have to pay for. 

You can also use it for vermicomposting, as it is an excellent source of food for earthworms. Another form of composting that you can use cardboard boxes for is dig and drop, where you simply bury kitchen scraps and leave them for passive decomposition. You can place the box into the ground up to its edges, then start filling it while ensuring the recommended greens: browns ratio in the mixture.

Why You Should Compost Cardboard

To reduce the impact of dumping cartons into the environment

By composting cardboard, you reduce the quantity of cardboard that ends up in landfills, which is up to 31%, according to the United States Environmental Protection Agency. 

Compositing is even better because it does not consume any additional resources or energy and instead contributes to the health of your garden. Now that many people have discovered the many benefits of using compost instead of inorganic substances for their gardens, composting can be the perfect way to get rid of all the boxes in your attic or right after moving.

It will improve the quality of your garden or flowerbeds 

What’s more, you will be able to reuse the cartons in a way that benefits your home rather than dump them and leave them to decompose in a landfill. The cardboard may not have much nutrition to add to the soil but is known to improve soil structure once added to farms and flowerbeds, thus improving drainage if you live in an area with plenty of clay soil, boost water retention in sandy soils, and encourage nutrient retention in all types of soil. 

If you have a lawn or small vegetable or fruit garden, or even plan to plant some herbs or flowers in pots at home, you can create some healthy compost material from your cardboard rather than rely on commercial synthetic fertilizers. By using cardboard for composting, you will save money on lawn care, boost the health of your plants, and reduce the probability of pest infestation and inorganic fertilizer use. 

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It improves the quality of your compost pile

One of the characteristics of a good compost pile is a balance of both green and brown waste. Green wastes are all sources of nitrogen and consists of fruit rinds, vegetables, grass clippings, weeds, plants, and other green organic matter. 

Brown waste, on the other hand, is a source of carbon and includes plant materials that are brown, such as leaves from the fall, wood, paper, and, of course, cardboard. If you live in the urban areas and are lucky to live in a town that allows its residents to create compost, then coming across hay, dried leaves, and straw may be difficult, and cardboard may be a more accessible and stress-free option due to storage.

By understanding the carbon and nitrogen composition of the materials you want to compost, you can categorize them correctly and ensure that your ration of green to brown materials is optimal. The ideal ratio of C: N is usually 30 parts brown to 1 part green, which translates to 6 inches of brown materials to 2 of greens. By composting the cardboard in your home, you will be able to make the number of brown materials you require. 

If the ratio is not met, the microbes will not have the quantities of carbon and nitrogen they require for food, which means that the rate of decomposition in your pile will reduce significantly. On the other hand, if you provide sufficient browns and greens for the microbes, they will grow rapidly, break down the matter in your pile, and raise the temperatures to optimal levels so that you have a great, healthy pile of humus waiting for your garden.

In addition to being a great source of carbon, cardboard’s bulky nature allows air to enter the pile and stay there due to the introduction of air pockets. Microbes, just like us, require oxygen to breathe and decompose the organic materials. 

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Cardboard, being a great source of carbon, is also known to accelerate the rate of decomposition, which will improve the structure and density of your compost. If you have a problem with foul smells in your bin, adding shredded cardboard will help you reduce this problem, as foul smells are associated with having excessive nitrogen-rich materials.