Can You Compost Cardboard? (Methods, Tips & Benefits)

We all have cardboard piled up at our homes. Be it from amazon shipment cartons, food or drink packages, or shoe boxes. So what do you do to get rid of this clutter? Have you ever wondered if you could turn this waste into a treasure for your garden? Or whether or not you could compost cardboard? If not, let’s find out now!

Cardboard can be composted and serves as a great soil additive. It contains carbon which makes it nutrient-rich humus for crops. However, it’s crucial to shred cardboard before adding it to the compost bin. Furthermore, cardboard containing plastic or shiny material should not be composted.

How To Compost Cardboard?

There are two methods to compost cardboard; the traditional method and the Lasagna method.

The method you choose for composting depends on how quickly you wish to get the compost ready and the time you have to monitor your compost bin. However, both ways are excellent for composting.

For composting cardboard, you need to choose a bin that perfectly fits your materials. Furthermore, ensure that the bin has a lid and is a perfect size.

Traditional Composting Method

The traditional method of composting cardboard is popular and widely used because it produces compost quickly. Let’s look into the process of composting.

Composting Method

Step 1. Shred cardboard into pieces

Collect all the cardboard boxes from your home. You may segregate large carton boxes, shoe boxes, egg cartons, pizza boxes, cereal boxes, juice packaging, etc.

Now shred cardboard into fine pieces. You might need a scissor or a paper shredder for this. Soaking the cardboard pieces with the help of a liquid detergent would help cut them into small pieces.

Also, you need to remove stickers, tapes, or labels from the cardboard. You can do this after shredding the cardboard or soaking them in water.

If you put cardboard without shredding, it may have air pockets in the pile, which blocks oxygen flow, slowing down the composting process.

Step 2. Start to fill the compost pile with Brown materials

Prepare a 4-inch layer of bed with brown material. First, add shredded cardboard material to the bottom of the compost bin and follow it with other brown materials like dried leaves, ash, straw, etc.

Brown materials are a great source of carbon and act as a food source for the microbes in your compost bin. C: N ratio in cardboard is 200:1, which proves it to be great composting material.

Step 3. Prepare a layer of Green materials

Over the brown materials, now it’s time to add some greens. Make a 4-inch layer of bed with green materials, including food scraps, kitchen waste like fruit and vegetable peels, yard waste like grass clippings, cow dung, etc.

Green materials are rich in nitrogen and help the microbes grow and multiply quickly, thus helping faster decomposition.

Step 4. Repeat the process

Repeat the layers until the pile is full (maintain a brown-green layer).

Once you have filled your compost bin with brown and green materials, cover it with a firm 2-3 inch layer of soil.

Step 5. Water your compost pile

Now it’s time for watering. Your compost pile should be moist. The ideal moisture content in a pile is 40-60%. Based on the wetness in your compost heap, add water or cardboard pieces to the heap.

Dampening the materials in your compost pile will help the microbes to degrade the waste by providing a suitable environment.

Step 6. Turn the compost pile

Check your pile every seven days to observe its condition by turning it with a shovel or pitchfork. Move the materials from inside out to ensure that the compost gets plenty of oxygen.

Turning the composting pile is crucial to allow airflow in your compost bin. It helps in the even distribution of moisture and creates a healthy environment for microorganisms to thrive.

Once you are done with the composting process, your compost will turn into fine soil in 6-8 months and can be used in your garden.

Lasagna Method for Composting

If you feel that shredding paper or cardboard is complex or do not have time to maintain your compost bin, there is an alternative method to compost cardboard.

Although time-consuming, the lasagna method or sheet composting is easier and does not require much labor.

Lasagna Method

Let’s see how to compost through the Lasagna method step-by-step.

Step 1. Arrange the cardboard sheet in the compost bin

First things first, take the cardboard and paper sheets and lay them in your compost bin.

Then, spray some water to dampen the sheets so that they can decompose. Now, cover these sheets with a firm layer of soil.

Step 2. Add some greens and browns to your compost bin

Over the soil, you need to add some green materials like kitchen waste, yard waste, and food waste.

Now add brown material like wood chips, dry leaves, and straw.

These materials act as food for microbes and provide the energy to break this food into soil rich with organic material.

Step 3. Repeat the process

You need to repeat the process by altering with cardboard or paper sheet, green material, brown material and fill the compost bin.

In this method, you do not need to water your compost pile or turn it.

Though it is easy to set up, it takes longer to produce the finished compost. Also, in this method, you cannot add the layers to your compost bin later.

Types Of Cardboard Used for Composting

Most cardboards are made of compostable packaging and can decompose well. These Carbon-rich materials can serve as a great source of organic material. But before using them for composting, you need to know which materials are suitable to compost.

Cardboards are classified majorly into three types.

  • Corrugated Cardboard: This type of cardboard is generally used for packing and is considered the best type for composting. 
  • Flat Cardboard: Flat cardboard that comes as a shoebox, cereal box, pizza box, juice packaging, etc., can be composted. But make sure that the pizza box or food wrap you want to compost is not greasy. Bacteria in the compost pile hate grease and repel it, halting the decomposition process. 
  • Wax Coated Cardboard: Such cardboard materials are coated with wax. It includes coated paper cups, milk packs, pet food bags, etc. The wax in these cardboards makes them difficult to compost.

Any cardboard with a shiny coating or plastic wrap should be avoided for composting as it might contain plastic or other polymers. You can soak the cardboard box and see if you can remove the plastic coating before throwing it into your compost bin.

Benefits of Composting Cardboard

Composting cardboard comes with incredible benefits. Here are a few you should know for sure.

  • As cardboard is a rich carbon source, it helps balance the organic-rich greens present in the compost pile.
  • Cardboard offers nutrient-rich organic matter that will be useful to grow plants.
  • Cardboard helps to enhance the airflow in the compost pile.
  • Cardboard soaks excess moisture from the compost heap, preventing it from becoming compact and leaking.
  • It does not release any harmful residues and is eco-friendly.
  • Carbon present in cardboard helps in the easy decomposition of the compost.
  • Cardboard (especially the thick corrugated cardboard) is known for its insulation property and is considered best for composting. In winters, it helps to hold the heat.

Additional Tips For Composting Cardboard

Using cardboard for composting helps you get off the unnecessary clutter in your home. Here are some of the useful tips you need to follow before composting cardboard.

Composting Cardboard
  • Shred your cardboard into small pieces to accelerate the process of decomposition.
  • Before using cardboard for composting, you need to take off the labels, tapes, or staple pins as they won’t degrade.
  • Use rainwater while composting as its pH is neutral.
  • To know the water content in your compost pile, collect some composting material and press it within your palms. If it feels dry, you need to add water, and if the water drops out when squeezed, you need to add more shredded cardboard pieces.
  • Turn the composting pile on every seven days to prevent it from matting.
  • To speed up your composting process, avoid using wax-coated cardboard.

Can Cardboard be Used Directly in the Garden?

As the cardboard is rich in carbon, it’s not mandatory to use it only through composting. Here are a few ways to use cardboard directly in the garden.

1. As a sheet mulch: When you start gardening, it is extremely laborious to clear the land and remove the weeds. You can use cardboard to avoid this. The cardboard acts as a sheet mulch, inhibiting the weeds from growing and providing organic matter to the soil.

For this, you need to clear the land and lay down cardboard sheets across your garden. Water the cardboard to keep it intact. You may also add compost over it to make the soil nutrient-rich. 

2. Use it for suppressing weeds: Using cardboard sheets in your cropland would suppress the weeds by preventing sunlight from reaching them. For this, lay cardboard sheets around your plants by making holes near their roots. These holes will help your plant to receive oxygen and water. 

3. Seed starter pots: Have you ever seen those tiny pots made of coir or peat for sowing seeds? These can be altered by using toilet paper rolls, paper towel rolls, or any cardboard which can be bent or rolled. 

For making the seed starter pots, you need to cut the paper roll at one corner, turn it to make the bottom, and seal it with glue.

Now you can fill the paper roll with soil and place your seeds. Once the saplings grow and are in 3 leaf stage, they can be planted in the soil along with the cardboard roll.

Frequently Asked Questions:

How long does cardboard take to compost?

It generally takes 6-8 months for the cardboard to decompose completely. However, the decomposition time depends on the type of cardboard used. Corrugated cardboard is considered the best for composting and can degrade quickly.

Is it better to recycle or compost cardboard?

Composting cardboard is considered better than recycling as it is environmentally friendly. Composting helps to control methane emissions and reduce carbon footprint in the environment.

Can you compost cardboard with ink?

Composting cardboard with ink is possible, but only when it is water-based. Few manufacturers, especially for making shiny cardboard, still use petroleum-based inks that contain heavy metals and are harmful to the compost. Therefore, it is better to avoid cardboard with ink for composting.

Can you compost waxed cardboard?

No. It is not ideal to use waxed cardboard for composting. The wax coating may contain chemicals, some processed ingredients, and plastic coverings. These materials may take longer to compost, and it is unknown whether they will be composted entirely or not.

Can you compost colored cardboard?

Only use brown or plain cardboard without any dyes. Avoid colored cardboard as it might contain some heavy metals. Although modern-day inks are made with vegetable dyes, you cannot assure what is used on your cardboard packaging unless it is mentioned.

Is cardboard brown or green compost?

Cardboard is a brown material used for composting. It is rich in carbon and serves as feed for the bacteria in your compost bin. The carbon-nitrogen ratio in cardboard is 200:1, and it helps to balance the organic-rich greens present in the compost pile.

Composting cardboard is a great way to manage waste at your home. So whenever you have any cardboard left after unboxing, don’t think twice and put it in your compost bin. And, after you’ve composted cardboard, if you have any questions about composting paper towels, we’ll walk you through it.