How to Shred Cardboard for Compost: 3 Easy Methods

I know many of you have been wanting to find a way to make some use for all of those empty amazon boxes you have laying around your place. If you’re reading this during the holiday season you may have triple your usual number of boxes collecting dust.

We live in an interesting time where the majority of the things we get are delivered to us. Most of these packages are cardboard so it only makes sense to find ways to recycle this paper pulp and give it a new life.

We will be going over: How to shred cardboard for compost.

What is Cardboard

I’m sure the vast majority of you know what it is because you see it everyday and it is a staple in your life, but the materials used to make it will help us decide the easiest methods to shred it for the purpose of using it as a “brown” layer in your composting bin.

Cardboard is largely made up of paper fibers/pulp which come from wood pulp or recycled cardboard. This pulp is then beat into submission and squeezed to remove the majority of the water from the wood using machines constructed for this purpose. The pulp is later pressed with an element of steam heat to get rid of all the traces of water forming a sheet that is your traditional cardboard

If the cardboard is corrugated it will have at least 2 stand sheets of cardboard with a fluted piece in sandwiched between giving the box more rigidity. The corrugated boxes are more difficult to shred and take longer to compost when they are not shredded properly.

1. The Water Way

As you have just learned or were reminded. One of the main processes of cardboard production is the removal of the water from the wood pulp. This is done at multiple stages and is obviously an important aspect of the structural integrity and rigidity of a cardboard box. Most of you have dealt with cardboard that has gotten wet and know it begins to sag and soften.

One of the big issues with shredding cardboard for compost is its stiffness and strength typically prevents you from shredding it by hand. We are going to change this.

The water way method is by far the easiest. All you add water to the cardboard box after flattening it and easily shred it by hand. This will add moisture to your compost as well as brown material with a two for one special. You can do this a few different ways:

1. The easiest method it to just sit your cardboard in your backyard and let your sprinklers do the job. Leave it out for a couple days and then go and shred it.
2. Fill a couple 5 gallon buckets with water and soak the cardboard in them after cutting them to fit with scissors or tearing them by hand
3. Get creative- put them in the back of your pickup truck and head to a coin operated carwash and spray them down, leave them out in the rain, soak them in an outdoor kiddie pool etc.

2. Edward/Edwina Scissor Hands

This method is one I am not a big fan of but it is still an option for those who find it more amenable or don’t have access to the proper resources for the water way. You can do this with heavy duty scissors (easy), a box cutter (medium), a kitchen knife (difficult) or any other sharp object you feel that you can safely wield and finish the task unharmed.

It is a simple method. You flatten the cardboard and cut it into a strips running the length of the board. Upon completing this task you will stack a couple of the strips on top of each other and cut them as finely as possible into a bag or bucket. You rinse and repeat until your pile of cardboard is all finely cut and then add it to your compost in the proper quantities. For better integration into the compost bin you can put the now shredded cardboard paper into your food scrap bin to soak up the juices and pour it all into the compost bin after a few days.

Safety is should be a main focus with this method. If using a box cutter or knife cut away from the body and make sure you are cutting over a surface that won’t be damaged if the blade penetrates. Wear safety gloves if necessary. And if you need a pair of heavy duty scissors I recommend These. 

3. Bonsaii

This method involves using a paper shredder to do all the hard work. It is the easiest method but comes with the largest upfront cost. This is my favorite method and the one that I employ the majority of the time. You do need to know that all shredders are not created equal and I’ve found the majority of them cannot shred cardboard paper, they will jam, overheat, short, the blades will dull etc.

I will recommend 3 that I have used with the first one being my favorite and the one that made the shredded cardboard you see pictured above

Shredder 1: Bonsaii Paper Shredder

Price: $209.99

Best Place to Purchase (lowest price): Amazon

Capacity: 18 sheet with 6 gallon receptacle

My Rating: 5/5 As I stated this is my favorite one. It is well priced and works well. Ive yet to have it jam and haven’t had any issues. If I had to guess I’ve shredded roughly 500 gallons of cardboard with it.

Shredder 2: Fellowes Powershred

Price: $318.99

Best Place to Purchase (lowest price): Amazon

Capacity: 18 sheet with 9 gallon receptacle

My Rating: 5/5 It does the same job as the shredder above outside of having a larger collection bin. This allows for more shredding before emptying.

Shredder 3: BONSEN Heavy Duty Paper Shredder

Price: $318.74

Best Place to Purchase (lowest price): Amazon

Capacity: 24 sheet with 9 gallon receptacle

My Rating: 5/5. This one has a large bin and allows for thicker pieces of cardboard to be shred. A bit louder than the the others but more efficient.

Keep in mind that you will most likely have to cut or tear the cardboard so that it fits in the paper slot. Also make sure you allow your shredder time to rest and cool down, I have never had one overheat but I shred throughout the day on a whim and not all at once.

Get to Composting

Using one of these 3 simple methods will put you well on your way to shredding cardboard for compost and using those old boxes to bring new plant life. Remember to pick a method based on your circumstances or you can use all three!!

Some key things to remember:

1. For the water way make sure the cardboard is soaked all the way through and soggy to the touch
2. For the scissor hand method, if your using a box cutter, make sure to have fresh blades or if your using scissors make sure they are ones that can be sharpened as cardboard will actively dull the blade. Also remember to cut away from your body and use safety precautions
3. For the shredder method, be gentle with your shredder, they are typically made for paper not cardboard. If you plan on buying one for cardboard alone I suggest getting a protection plan just in case of failure down the road, as I said all of shredders are not created equal.