How to Compost Cardboard

Cardboard is often a free and abundant resource which you may accumulate from packages or from stores or sources who give it away at no cost.

Let's look at how to compost carboard, so you can recycle this resource for use in your garden.

Can You Compost Cardboard?

Believe it or not, unbleached brown cardboard boxes are generally safe to compost. They typically use soy-based ink and a flour and water paste to glue the boxes together, which makes them relatively safe to break down in your compost pile.

It is important to note that you should avoid using cardboard that has any sort of glossy finish or is coated in plastic, as these materials won't readily break down and will contaminate compost.

Problems With Composting Cardboard

Composting Cardboard

Sorting Cardboard

Safe Types of Cardboard

Types of Cardboard to Avoid

I almost always use unbleached brown cardboard. Most inks these days are soy based though, and I've definitely shredded a few colored boxes.

Never compost laminated cardboard, however, and be sure to remove all labels, tape, and staples

How to Shred Cardboard for Compost

I used to try and cut all my cardboard with scissors, but quickly found that to be futile. For a while I tore my cardboard into pieces by hand, but this is exceptionally time-consuming and you can easily buy back this time with an investment to speed up the process.

What I found was that by using a heavy-duty shredder I'm able to streamline the process and use my time and energy much more efficiently.

The shredder turns cardboard boxes into cardboard confetti in seconds, and a few minutes of light works gives me a bin full of shreddies!

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I use a 12-sheet micro-cut shredder, which absolutely shreds cardboard like its butter. The description says it won't do cardboard (for liability reasons I'm sure) but all the comments from gardeners using it for cardboard speak for themselves.

These shred-puppies can turn even the thickest cardboard boxes into ridiculously small, easily compressed, manageable pieces that are perfect for composting. Just peel apart the two layers first if you have double-corrugated cardboard from extra-thick boxes.

There's nothing more satisfying than turning a sky high pile of cardboard boxes into a super manageable sized amount of compost food.

It has saved me countless hours of tearing cardboard by hand, and has made my composting process much more efficient.

In fact, a large portion of my compost is made up of shredded cardboard. It breaks down quickly and helps to create a nutrient-rich soil that is perfect for growing healthy plants.

Composting Shredded Cardboard

Check out our guide to Making Incredible Compost to learn about composting your cardboard shreddies.