How to Shred Cardboard for Compost – 7 Ways


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There are so many things you can compost that you may have never considered, and cardboard may be one of them. Cardboard composting is easy and a great source of browns.

As long as your cardboard does not have plastic coasting, it is safe to compost and is included in the browns portion of your compost.

To ensure the cardboard will break down quickly in your compost, you should shred it first.

In this article, I will talk about why shredding cardboard boxes is beneficial and list some cardboard-shredding methods. I’ll also include some helpful products as examples. 

Why Shred Cardboard for Composting?

Shredding cardboard will speed up decomposition and enable you to mix it into your compost easier.

If the cardboard is added as large cardboard sheets, it increases the chance that large clumps of it will not decompose, which may lead to problems with your compost pile.

If you are adding cardboard to your worm farm (vermicomposting), then breaking it into smaller pieces will allow the worms to be able to eat it more efficiently.

Keep in mind that cardboard does not carry extra nutrients for worms, although they do love it! Just make sure that you are giving them a healthy mix of foods for nutrients. 

There are a number of different ways to shred cardboard and not just ripping it up by hand. 

7 Ways to Shred Cardboard

Shredding cardboard can be a pain in the butt. It takes time and energy, and sometimes you have to do it by hand. But there are ways around this. Below I’ve listed the best methods to shred cardboard.

But first, before shredding, it is important to remove any pieces of tape, plastic, or staples because they won’t decompose.

Some gardeners do put bits of cardboard in their compost heaps with the tape still attached and then remove the tape once the compost is ready. I find it far less time-consuming to remove the tape beforehand, and shredded plastic can be tough to spot.

You can still add the staples to your heap as they will add extra iron, but if you’re using an electric shredder, you may still want to remove them to avoid the chance that they will damage your shredder blades!

1. Garden Shredder/Wood Chipper Shredder

If you’re already shredding garden waste, then a garden shredder or wood chipper is ideal for preparing cardboard for composting.

This is the best way to deal with a large amount of cardboard waste but could be overkill if you’re only doing small amounts for a worm farm. I wouldn’t recommend buying a garden shredder just for cardboard.

But if you already have one to deal with woody garden clippings, then this a chipper shredder is the way to go. Here’s a list of the best chipper shredders for composting.

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2. Industrial Paper Shredder

Paper shredders are less costly than garden shredders, but can do the job just as easily. You’ll need to get a heavy duty paper shredder that can shred large amounts of paper at one time.

Admittedly, it is more time-consuming to use a paper shredder, and you may have to cut the cardboard down to smaller sizes first.

If you’re taking this route, go for a 12-sheet (or higher) paper shredder. Paper shredders give your cardboard a perfect consistency to add to your compost and are the weapon of choice for most cardboard composters.

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3. Box Cutter

If you’re cutting up your cardboard manually, you can’t go wrong with a box cutter. These sharp blades are specially designed to slice cardboard boxes.

 Be very cautious with these tools, and always wear sturdy gloves when using them. The blades are often retractable, and it is worth getting into the habit of retracting them whenever you aren’t using the knife. They usually also have replaceable blades, so when the old blades become blunt, you can change them out.

Using a box cutter is the most labor-intensive method of shredding cardboard because it’s all manual. It’s best to cut the cardboard down into roughly 1-inch strips for the decomposition process.

Box cutters are also a handy tool to have if you are using a paper shredder, as they will help you cut your cardboard down to a size that fits into the shredder. But using them on their own to shred large amounts of cardboard isn’t as practical. 

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4. Electric Scissors

These are a step up from using a box cutter and will make the job more manageable if you regularly cut up small amounts of cardboard.

One tip if you are cutting corrugated cardboard to make your job easier is to cut with the grooves, rather than across them.

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5. Electric Hand Saw

If you’re looking for something with more power and speed, you could try electric hand saws like this hand-held mini chainsaw!

It has the added benefit of being able to saw through small branches, making it perfect for pruning too.

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6. Soak The Cardboard

If you don’t want to spend money on tools to help you break up your cardboard, then you can soak it and tear it up with your hands.

Soaking the cardboard also means that any stickers or tape will be much easier to remove. Cardboard that has a plastic coating, like cereal packets, will also be able to be composted if soaked. The plastic layer can be peeled away after just a couple of hours of soaking in water.

Soak standard cardboard for at least 12 hours, longer if the cardboard is thick. Once it is soggy, it will be easy to tear it into pieces.

If this seems like it would be a bit too messy for you, then you can use a garden fork. Use it to stir the cardboard in the water, which will break the cardboard up effectively. Alternatively, you could use an electric mixer.

Whether or not you dry out your cardboard is up to you, but if your compost heap or bin is too wet, then I recommend drying the cardboard pieces first to enable them to help soak up any excess moisture. Otherwise, you can give it a quick wring out, like wringing a washcloth, so it’s not too wet.

If your compost is on the dry side, then adding wet cardboard may be beneficial. If you’re using it in a wormery, wet cardboard will reduce how much water you need to add later.

7. Lasagna Gardening

While this is not a shredding method, it is still a way to use cardboard in your garden.

When adding alternate layers of organic matter to your raised bed, add one layer of cardboard in between layers of green material. It’s like layering when making lasagna. 

Using your cardboard in this way is an effective way of using cardboard without cutting it down. It may also help you with your brown layers if you don’t have many woody garden cuttings to add.

Shredding Cardboard Boxes Final Thoughts

There are a number of ways to shred cardboard. While some methods require specific tools, others are as simple as soaking the cardboard before tearing it apart.

The most important thing to remember when shredding cardboard is that it should be shredded into smaller pieces. This makes it easier to decompose and be digested by worms.

Here are more articles on composting ingredients: 

Shredding Cardboard FAQs

Can you shred cardboard boxes?

Yes! Shredding cardboard boxes can be easy and cheap. All you need is a pair of scissors, a box cutter, and some patience. For quicker and easier shredding, you can use a chipper shredder, industrial paper shredder, and electric hand saws. 

Can you shred cardboard in a chipper shredder?

Yes, you can shred cardboard in a chipper shredder. However, you should be careful when using a chipper shredder because they work by cutting the cardboard into small pieces and then crushing them. This means that the shredded paper could contain sharp edges.

How much does a cardboard shredder cost?

A cardboard can shredder cost around $100-300 depending on the size and features. For cardboard, you’ll need a high-quality, heavy duty paper shredder to be able to shred corrugated cardboard. Basic paper shredders will not be able to feed cardboard through to shred it. 

Do I need to dry the cardboard after soaking it?

Whether to dry the cardboard or not depends on the situation with your compost pile. If the compost pile is already dry, then there’s no need to dry the cardboard. You can simply add the soaked cardboard directly to the compost pile. On the other hand, if your compost pile is very moist, then you might want to dry the cardboard first. The reason for this is that wet cardboard will absorb more water than dry cardboard. Soaking the cardboard will remove some of its moisture content, which will make it easier to shred.

Do you really need to shred cardboard for a worm bin?

Yes, you do need to shred cardboard for a worm bin. Worms like wood pulp, which is what makes up most of the cardboard. Worms will have an easier time eating shredded cardboard. If they can’t eat the cardboard, you won’t be able to get compost from the worm bin.