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Why Worms Like Brown Cardboard

brown cardboardIf you know one thing about red worms, it’s that they’re crazy about brown cardboard. After all, why not? It’s the perfect bedding, the perfect jungle-gym, and the most readily available foodstock.
Have you ever wondered why they eat it?
We’d like to jot down some of our thoughts on this topic and present some different theories that are floating around out there. We’d love to hear your feedback and hear your thoughts so be sure to leave a comment below!

Why Do Worms Like Brown Cardboard?

Before we dive into some different theories, let’s first discuss what cardboard is comprised of.
First, there are two types – paperboard and cardboard. Paperboard is cereal boxes, 12-pack soda boxes, empty toilet paper rolls and the such. The other kind is corrugated cardboard. Corrugated cardboard uses glue to seal the corrugations. Paperboard does not have any glues holding it together, and the two are made differently. This is an important thing to remember as we talk about the theories below.
Theory 1: They like the cardboard glue. Corrugated cardboard is held together by glue – which is why it unravels and falls apart when wet – and also explains why certain places feel slippery when wet. This glue is said to be made from cornstarch, and therefore, contains nutrients in it. However, this is only a theory and there has been no substantial evidence on that front. Worms eat shredded paper and paperboard too, so the glue can’t be the only reason worms enjoy feeding on brown cardboard.
Theory 2: There is actual food found in cardboard. Cardboard collects and houses many species of fungi due to the fact that it’s a material that’s high-carbon and nitrogen. Secondly, since brown cardboard is often used to hold and transport organic foods, there is undoubtedly a small amount of food juices and rotting waste that seeps into the cardboard. This means you have a good chance of finding a microbial population in the cardboard and we all know worms love microbes.
There is a business in Vernalis, CA that used to use cardboard and paper sludge as their only feedstock. Now, they use bits of vegetable waste. But, it worked for a while!
At least we have some answers here. Undoubtedly there are more, so please share your ideas! Most importantly, the worms seem to thrive by brown cardboard and seem to love eating it! Don’t forget to shred, or cut up your brown cardboard to make it easier for the worms to digest and more suitable for bedding. Cardboard is the perfect bedding because it allows air and gases to flow freely, it holds water, keeping the worms moist and also absorbs water to prevent too much water from swamping your bedding!
Uncle Jim’s Worm Farm is a vermicomposting company that specializes in worm farms, kits and the famous red wiggler. The above image is not our own.
Image courtesy of

3 comments on “Why Worms Like Brown Cardboard

  • I believe the answer is a combination of hypothesis #1 and #2.

    The glue is a starch, which is a constituent of carbohydrates and the cardboard is fibrous. Cellulose material needs fungus to break down. Cardboard is also porus, so it will absorb water and hold on to it.

    Worms and other composters feed on carbohydrates, fungus, and water. Everything damp cardboard has.

    When i garden, i put down a thick layer of corrugated cardboard or newspapers (newspapers for smaller plots but i am using more and more cardboard). I don’t till, plow, or even remove any growth before carpeting the garden. I plop down a 5 gallon bucket of compost for every plant, then cover everything with raw wood mulch.

    Weeding is minimal. Water retention is excellent. And the amount of worms i end up with 2 weeks later is insane, leaving all sorts of great castings behind.

  • In a worm book years ago, it said that worms loved cardboard because it was made of animal hooves. Thus cellulous I guess. It also said that “sewer sludge” was the absolute best food for growing large worms. Perhaps one could go down to the city sewer repository and ask for some sludge to feed your worms. LFL.

  • Ron Madsen says:

    Cardboard is a GREAT bedding and cover for placing over a feed area in your bin. The shredded for bedding and flat section moistened to cover an area for the top feeders. The little guys seem to love it! It does break down slower than shredded newspaper though, so use that to your advantage when planning and placing bedding materials.
    I do believe that old paper egg cartons are the ultimate “cardboard” as they seem to be 100% cellulose, provide some irregular surface area for microbes and aeration, holds moisture very well, and decomposes at about the same rate as newspaper. Mixing this with newspaper will get the perfect texture and density needed for your bin while all materials are usually readily available, free, and would be thrown away in most households.


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