This pile has been sitting for almost six weeks untouched. I had it covered with a tarp. I peeked under and decided to just turn the top nine inches. Very surprised to see coffee and shredded cardboard very visible and discernible. No bad smell. Big activity present. Moist to the touch.
What am I doing wrong?
by rkd80
19 Comments
Needs more nitrogen (greens) most likely, its easy to go over with cardboard.
And not all cardboard is created equal, some of it gets waxed or coated and takes longer to break down.
But that does look maybe a little dry to, grab a handful, squeeze, you should get 1-2 drops out.
And here is a good balance if just using cardboard and coffee….
You need ≈ 0.16 to 0.68lb of shredded cardboard (about 2.5 oz) per 5 lb of coffee grounds to reach a 30:1 C:N ratio.
(see my post here if you really want to get exact about the 30:1 thing)
[https://www.reddit.com/r/composting/comments/13i5s8s/for_those_who_want_to_be_more_exact_with_their/](https://www.reddit.com/r/composting/comments/13i5s8s/for_those_who_want_to_be_more_exact_with_their/)
Seems like it may just be taking longer than you’d hoped. Can’t see the temp but you said big activity present so let it do its thing.
I’d add more moisture
I was going to guess that it’s too dry. I’m lazy and just throw complete boxes in my pile and they disappear, so I’m not much help.
I have taken to putting my shredded cardboard in totes and SOAKING IT FOR a MONTH. It breaks down into something dark that looks like leaves. I am experimenting also with adding nitrogens, sometime corn cobs and vegetable scraps, sometimes chicken manure.
I have cardboard similarly shredded. It is probably 1/3 of my carbon. It takes more added nitrogen over time to break down, similar to my pine needles mulch.
I turn and wet (typically pee) it every few days. But it’ll take care of the cardboard in a few weeks.
I don’t use a tarp. I have mine in direct sun until 2 pm when my house occludes it
Patience is the only missing ingredient here.
Have you peed on it enough?
I never expect the outermost layer of material to break down very well. When I turn my piles I strip off the entire 6 inches of outer surface, throw it at the bottom of the new pile, and then decide how “done” my core material is.
This all goes double for the top of the pile, which drains first and has no layers above it to inherit anything from.
In other words, I don’t think you’re doing anything wrong, except perhaps expecting perfection through every inch of the pile.
I have the same problem in my tumblers. Everything else turns black, but the shredded cardboard remains recognizable.
I’m here looking for answers, also.
I plan on using the compost anyway and let the cardboard continue breaking down in the ground.
Why cover with a tarp? A lot of rain or are you trying to trap in moisture? Either way. Some cardboard can be treated with a wax coating. It takes more time to absorb moisture and break down. Pile needs more water and turned.
As other posters have said think this is just a moisture and time issue. The cardboard in the middle of the pile is probably breaking down. Turn it, water it and wait for it.
Even if you have some shreds visible, you can incorporate it all into your garden. Most commercial bagged soil has shredded Mulch pieces in it.
throw is some earthworms!
I’ve had the same experience in my own compost pile with cardboard taking forever unless I really go at it with the hose or mix in a decent amount of grass clippings and kitchen scraps. Now I try to rip everything into even smaller pieces and make sure it’s all mixed and damp, makes a big difference. Don’t worry though, it’ll break down eventually!
If you can find or already have access to mycelium; for example, a patch of wet, decaying leaves with white stringy growth a few inches down, it can help tremendously. I’m not in the city myself, but I’ve seen people on Facebook Marketplace in SLC selling spent mushroom blocks pretty cheap, so I assume other major cities have similar listings. Those blocks will happily eat through cardboard and help create a much healthier soil ecosystem.
One way I’ve had good success cultivating wild mycelium (which is harder to come by in the windy high desert I call home) is by running green Siberian elm and Russian olive branches through my electric wood chipper. As long as the chips stay moist with rainwater, are kept shaded, and stored in a box or yard waste bag, they usually colonize quickly. If I leave them alone for a few weeks, I typically find a ton of mycelium throughout, and if I let it fruit, I get a type of inkcap mushroom (I forget which species). That particular fungus eats up wood chips and cardboard better than most cultivated varieties in my experience.
Got to be honest – I’m sure cardboard has crazy chemicals in it
I use all types of carboard. i even use cardboard from like Amazon or costco packages but it always breaks down. :)I’d add more moisture, and pee!♡
Looks like you still gotta soak it 24 hours before going in the pile (water, urine, unsulphured molasses).
When you skip soaking, the cardboard just sits dry in the pile, not breaking down, and sucking up the moisture around it.
Once soaked before adding, it softens quickly, becomes pliable, and stops blocking airflow or soaking up nearby moisture like a sponge.
Goal: Accelerate decomposition of cardboard in compost.
Obstacle: Dry cardboard resists breakdown, especially when layered.
Solution: Hydrate it before layering to:
1. Disrupt the lignin and cellulose matrix – Water weakens the bonds that keep cardboard stiff and laminated.
2. Speed microbial colonization – Moisture activates fungi and bacteria that digest carbon-rich material.
3. Improve integration – Wet cardboard molds around nitrogen-rich material like grass clippings, creating better contact and a balanced C:N ratio.
I think you aren’t turning the whole pile if I understood your caption correctly? I find the turning and the manual shifting and agitation is where a major benefit lies with compost. Aerates, mechanically breaks things down and therefore gives microbes/bugs and worms more access to a wide range of food and carbon (home, roughage etc)