Cardboard ‘n’ Coffee Vermicomposting

Ever since emptying out my wooden backyard worm bin it has been sitting empty…well, sort of. After a little while I started basically using it as a cardboard storage bin! I have stacks upon stacks of cardboard coffee trays (thanks to the efforts of my wife’s helpful co-workers), and the sheer quantity of them taking up space in my house and in the shed was starting to become a wee bit aggravating (sad, but true – haha).

It didn’t take long to essentially forget about the contents of the bin (out of sight out of mind) while I was busy with my various gardening projects, but I was reminded once again when I was faced with the task of cleaning out a plastic garbage can containing old brown paper yard waste bags that has been sitting open on my deck since last fall! Needless to say, there was a lot of stinky stagnant water in there (perhaps the rotting potatoes that somehow found there way in there contributed? haha), and of course the stinky, soaked yard bags. Just as a funny aside, I also found at least one or two fat Red Worms living semi-submerged in the upper zones of the soggy paper bags! They never cease to amaze me I tell ya.

While thinking of a good place to dump most of the water and compost the wet bags, I suddenly remembered my stash of (essentially dry) cardboard in the wooden bin. And thus, my “cardboard ‘n’ coffee vermicomposting” project was born!

The first thing I did was pull apart a bunch of the coffee tray stacks (i.e. separate the trays from one another), although I did end up leaving plenty of stacks as-is, simply because I didn’t have the time to do them all. My aim was to provide a lot more surface area for soaking up moisture and worm/microbe habitat.

Next I simply dumped in the wet contents of the garbage can, potatoes at all!

I then added a bunch of aged, used coffee grounds, some vermicompost and some rock dust for good measure.

Finally, I gave everything a good soaking so as to help get the ball rolling!

I don’t have any formal plans for this experiment – just going to fly by the seat of my pants as per usual. My main aim is to see what the composting critters can do with all this cardboard by the time late fall rolls around. While I’ll almost certainly add more grounds along the way, I am using them more as a water-holding filler (and N-source), so I won’t go too crazy with them. I may however add lots of old coffee filters.

Other than that, I will likely just water the system periodically and see how everything is coming along down below!
Should be interesting.

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  1. Now that is very cool!

  2. Love this one! I personally started throwing some in whole in my worm bins.I just left them on top.Then i decided to do a whole stack standing up.Boy that was funny! Looked like if you would have used a whole stack of pizza boxes,you could have called it the leaning tower of pizza!LOL! It fell over and sunk into my worm bin.Never made it out the bottom as what we know as cup holders.
    I just got done doing a whole phone book intact.Wish i would have noted a start date.But they ate the whole phone book.Pretty neat watching how other creatures help out making voids that the worms infiltrate!
    Man worms are fun!

  3. Not sure you are going to be happy when the potato’s start to sprout! They are almost as bad as pumpkin seeds. 🙂

    • pam
    • July 18, 2011

    I am just starting to put my bin together and wondered about the cardboard.Do I have to cut it all up in small pieces,I have been doing that and it’s a lot of work. Or can I put bigger pieces in there. Also as far as paper goes does it make any difference? Is all paper and junk mail ok? Hope the questions aren’t too silly but I want to do it right the first time.


    • Bentley
    • July 18, 2011

    Hi Pam – no such thing as “silly” questions.
    Using shredded cardboard is much better than sheets of cardboard since there will be a lot more surface area for microbial colonization, moisture absorption etc. Sheets of cardboard just tend to be really annoying to work with, and take much longer to break down. You might try soaking your cardboard in water before ripping it up – this can make it a lot easier.
    I wouldn’t recommend using all types of paper – stay away from the glossy stuff completely, and color (with photos etc) stuff in general as much as possible. In the past I have recommended that people steer clear of bleached white paper as well, but I think you should be totally fine as long as you soak and drain in a couple times before adding it to your bin. Brown paper and newsprint type paper are great.

    • Bentley
    • July 18, 2011

    P.S. I don’t think I will need to worry about these particular potatoes, Jerry, since they froze solid over the winter – but I definitely know what you mean! I have them popping up all over the place in my gardens this year.

    • Brenda Bonner
    • April 27, 2012

    I would like to know if anyone knows what goes into the making of coffee trays. If any chemicals are used. They smell terrible, which is not my concern, I have a son with autism that is addicted to the smell. We are just looking into every avenue because of his behavior outbursts and thinking maybe this has something to do with it. I would appreciate any help as it is very hard to find something to replace this behaviour. Thank you so much for any input.

    • James Penrod
    • August 24, 2012

    I am setting up my vermibin and I’m curious about coffee grounds. You noted that you used aged, used coffee grounds. What do you mean by aged? I dry them everyday and store them in a plastic feta cheese can. Do they need to be left out in the elements like manure? Also, I french press my coffee and there seems to be a good bit of caffeine left in them. Would I need to leach the caffeine more. I have grounds everyday and my neighbor has offered theirs also. In fact, at this point, the most abundant items I have on a weekly basis is coffee grounds and egg shells. I need some idea of a good mix for adding these items routinely.
    Thank you,

    • jolj
    • August 15, 2015

    First post 2011, last post 2012.
    So how did the project work out? Would shredded office paper work well?

    • InspectorNashBridges
    • March 15, 2020

    I got a 5 gallon bucket of compost for free. I noticed a few worms. Then I just started throw in away my coffee grounds, food scraps, junk mail, and cardboard into the bin. I just folded down the boxes to shove them in. When the bucket was full , I left it out in the yard. The worms ate everything. Just in a 5 gallon bucket, without a cover. I started another bucket with the same household refuse of food, newspaper, cardboard, mail, et cetera. Threw in some worms. And they started partying. Eating everything and reproducing. I tried my best , by hand, to pick out the worms from bucket 1 and put them into bucket 3, which started another population. Then used the compost in bucket 1 , with worms & eggs , in the yard …….. As bucket 1 emptied to about 1 gallon of compost, worms, and eggs, I began adding my garbage. 1 bucket of worms turned into 3. Now I have about 6 containers of worms, all with varying stages of compost. I use the compost as needed. 6 buckets, left out and uncovered. Free range worms. I don’t care for the worms. I don’t cut up the food. I only break down big boxes enough to cram into the bucket. Overnight condensation, morning dew, and rain provide moisture. I just don’t see why so much care and attention go into this. I don’t do anything other than throw garbage away, and the worms thrive.

    • jolj
    • April 25, 2020

    INB, did the 5 gallon buckets have drain hole & do you have a picture for us.
    Love the ideal & I have a few old buckets laying around.

    • InspectorNashBridges
    • April 25, 2020

    Drill holes. Stack the buckets. Worms can migrate up through the holes.

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