Why Do Red Worms Love Brown Cardboard?
I recently received an interesting question from one of our regular readers, Dave P.
I didn’t actually plan to publish it (and my response) here, but Dave thought it might be valuable to get input from others (i.e. Bentley’s response was pretty lame! haha!). Joking aside, I think Dave is right about this being a good potential topic for discussion. Directly below Dave’s question, I’ve included my initial email response (with some minor edits), followed by some additional thoughts added when I put this blog post together.
Over the last few months two things have contrived to make me
ask “why do worms love plain brown cardboard”?
1. I have two 1M cubed compost bins. I recently emptied (bar a few
worms) one and started a new one. I had it about two feet deep with
fresh garden waste, a few buckets of kitchen waste.
2. I happened to have a few items delivered in plain brown card, as
per Amazon books? Nothing special, just brown card. Soak it in water,
pull it apart and leave it for the worms.
Result? My garden compost is magically turned into fantastic
What is it about cardboard that makes them start chomping? An old
‘yellow pages’ book didn’t go down half so well. Yet there is no sign
of the plain card?
I’m mystified. I can’t see any food value in it? Roughage?
GREAT question, and something I myself have certainly wondered about over the years. Something I saw suggested once may hold the key. Some have suggested that it might be the glue used in this material that provides the food value – all those layers get stuck together somehow, and it’s probably somewhat similar to that paste we used to use in pre-school. Pretty innocuous stuff, but likely containing some nutrients (polysaccharides for the microbes? I dunno).
The worms seem to love using it as a habitat as well – worming their way down the channels.
Anyway – I guess I’m really not sure at all – but I do LOVE the stuff! If only it was a lot easier to shred it up!
I managed to track down the source of the “cardboard glue” theory mentioned above. It appeared in a Worm Digest article called “Paper Pulp Alone as Redworm Feedstock?!” (Worm Digest, Iss. #22, p.16). Here is the exact quote:
“Though the glues in corrugated cardboard are thought to supply a significant protein source, this has not been substantiated”
The article also touches on the fact that high-carbon (and low nitrogen) materials like cardboard can be readily colonized by many species of fungi. Given the fact that most of use (who use cardboard as bedding), are also adding other “food” materials (typically with higher nitrogen content), it becomes a bit easier to see how the worms might find the cardboard as appealing as they do. It soaks up juices from the rotting food waste etc, and undoubtedly develops a pretty substantial microbial population as a result.
Anyway – just my 2 cents (with some assistance from Worm Digest).
Thanks for the cool question, Dave! Hopefully others will add some input as well.