Shredding cardboard

I got the word out that I'm composting and hoping to buy land for permaculture next year. My friends are very helpful, and one of the ways they help is to deluge me in cardboard for my composting. I truly appreciate this, because I never lack green material for my bin (one call to a landscaper friend does the trick.)

The problem is cutting/shredding the cardboard into a useable size for composting. I have spent hours in my driveway with a razor knife, hacking a mountain of cardboard boxes into a mountain of cardboard chips. I priced out machines to do the job, but they're all designed for large commercial operations: they're bigger than anything I need and cost a fortune. Does anyone have a simple method to save my aching forearms?

Soaking cardboard in water makes it very easy to tear. In the past I've had an old bath to soak cardboard (and newspaper) in. You can also leave cardboard outside to break down (depending on your climate and how much rain you get). Use it on paths first. I sometimes cover my compost with a sheet of cardboard, which starts the break down process. If the cardboard is boxes, you can store things like leaves and compost itself in it, then when it breaks down, compost the cardboard.

I'm sure there are lots of other ways to break down cardboard in bulk, but it would be good to know what your climate is.

Rose, I live north of Detroit. My USDA zone is 5b to 6a.

Hi Chris, I don't know what the means (we don't use that zone system where I live). I'm thinking how much rain you get, and whether the climate is drying, are the issues (cardboard breaks down naturally in climates that get a certain amount of moisture).

Ah, I see. Here's a brief synopsis of what you're looking for.

www.bestplaces.net/climate/county/michigan/macomb

30 inches ≈ 72 cm; 82.4ºF = 28ºC; 17.9ºF ≈ -7.8ºC

Our growing season runs from mid to late May until early October.

After reading your post I walked out to try something a few minutes ago. I had my wood chipper out today using the side leaf mulcher for the mountain of leaves that are accumulating and found that if I tear the cardboard into 6" wide long sections it shreds them like a champ.

Ok, so quite wet then. You could probably break down large amounts of cardboard outside over time. You can probably even get some local fungi to help.

I use the shredder we have at work to shred cardboard. Works it like a champ. It's small, the size of a waste bin, but it's pretty strong for an office shredder.

When I started my garden, I wanted to do Hugelkulture raised beds, but I didn’t have any logs to start with.
I went dumpster diving and collected a lot of cardboard boxes to make my own logs. I folded the lid too the largest box, into the box itself, then slid another box into the first and folded its lid inward.
I continued this until I had a pretty solid paper log. Then I filled any gaps with newspaper and used bathroom paper hand towels. I laid the cardboard logs into the configuration that would best work for my garden and covered everything with grass clippings.

I tried a variety of seed starts but Nasturtiums, comfrey, society garlic, melons, tomatoes and pumpkin type squashes grew the best that first year. Not great, but acceptable for the first year.
I now have access to some wood branches and I cut them into 6” long sections and stack them vertically in the boxes and cover them with kitchen waste and then grass clippings.
In either case the cardboard holds a lot of water, but the branch wood boxes actually push water back up through the mulch and into the plantings above.
While the cardboard box logs hold the water into the center of the structure and the plant roots have to grow farther down to get access to the water.
Biologybill

Interesting idea, William. I wonder: how will the cardboard affect the longevity of your hugel beds? Clearly it will break down much faster than solid wood.

Hey Chris
You made me curious, so I dug 8 holes around the garden and I can’t find any cardboard logs. I may be looking in the wrong places, but they seem to have completely disappeared after a year and a half.
When I started I didn’t have access to dirt and what dirt there was, was scrapped off with an end loader. When the grounds people tried to get rid of the English ivy that had been growing in the garden plot, for the last 30-40 years. All I was given was a large rock, with a layer of gravel and clay.
So for my needs the cardboard and grass clippings have turned into black mulch. If I were to do it again, I would put grass clippings and kitchen waste between each layer of cardboard.
All organic material is going to break down over time. When it does, start all over, knowing that you are enriching the earth.

As a friend in Arkansas said, “When hard times come, people think all they have to do is stick a few seeds into the ground and they will be able to feed themselves. It doesn’t work that way, you have to improve the soil first.”
Biologybill

So it sounds like using cardboard "logs" the way you did was a fast way to build soil. Your technique was based on hugelkultur, but your result was more akin to sheet mulching because you used a medium that broke down so fast. Good thing, too. It sounds like you needed usable soil in a hurry.

Hi fellow composters!

My friend an I bought a chipper. He has worm bins that he gets the juice out of to pore on plants (forget the name of it atm) but worm bins take lots of card board. It's very time consuming like you said to tear the card board up. So the shreder works great for him. I have some woods to clear an can shred my leaves up more (so they compost faster).

Seen it on the way home from work an made a deal to go halfs. Guy wanted 400, looked it up, they go for 750 new and this one was in pretty good condition. Asked him if he would take 350 (always gotta haggel). So 175 a person, if one person wants their money back, the other one has to buy him out or the item goes back up for sale. The terms we agreed to.

Reviving this thread 7 years later!  I want to try using my wood chipper to make use of the insane amounts of cardboard I accumulate.  

Does anyone have a super easy method of getting the tape off it?  I hate the idea of spreading tiny bits of plastic everywhere if I were to chip it up, but perhaps it’s not that bad and easy to remove.

In the past I’ve cut off the portions covered in tape but it’s time consuming. I’m sure some here just let it compost and then pull the intact tape off. But I’m afraid chipping it would create tiny pieces.

I hear you; chipping would result in small plastic bits everywhere.  I've stripped a lot of tape with no insight for a better way.

Perhaps you could convince some kids that it's fun to rip off tape!

I use a razor knife and just score the cardboard through the first layer or so and then peel the tape and the top layer of cardboard at the same time.  It isn't perfect but it's better than fighting with the tape.

Seth Marshall wrote:

Does anyone have a super easy method of getting the tape off it?  I hate the idea of spreading tiny bits of plastic everywhere if I were to chip it up, but perhaps it’s not that bad and easy to remove.

In the past I’ve cut off the portions covered in tape but it’s time consuming. I’m sure some here just let it compost and then pull the intact tape off. But I’m afraid chipping it would create tiny pieces.

It's easy enough to pull up out of the decomposed humus if its still in long tape-like strands.

So while your chipper makes quick work of it, you're left with the obnoxious task of peeling all that tape off of each box, one at a time.

My solution is to stack the cardboard, one layer at a time, throwing a handful of soil or compost in between each layer and soaking each layer as the stack slowly rises.  I try to stack it on a 45 degree angle, so that there is "end-grain" exposed at the top.  That way water can more easily flow down through the layers rather than just soak the top layer which shields everything below from moisture.  This cardboard lasagna is fungal heaven.  Within months, the entire stack will be inoculated with fungi, and within a year, the whole thing will decompose.

Three keys:  1. It must be kept evenly moist.  2.  Its best to use rainwater or some other non-chlorinated water source.  3.  Once the whole stack/lasagna has been built, it works great if you can cover the entire thing with 6 inches of compost, again, exposing the end-grain of the cardboard to the fungal-rich compost.

If you want, you can create a fungal slurry by picking a bunch of mushrooms after the next hard rain and blending them up in your blender.  If you poured a little of that on each layer of cardboard, it would accelerate the growth of fungi.  But that isn't necessary, as any good compost pile if full of fungal life, so just throwing a bit of compost and/or soil between each layer of cardboard should be all the fungal spores you'll need.

How do you get the tape off?  8 months from now, you run a hay-fork through the crumbling remains of your cardboard lasagna and rake those intact tape pieces out.

What about toxic gick that may be on the cardboard?  Research has shown the tremendous toxic remediation qualities of fungi.  Let the fungi eat it all up, if there are nasty things in or on the cardboard.

Marco Banks wrote:
How do you get the tape off?  8 months from now, you run a hay-fork through the crumbling remains of your cardboard lasagna and rake those intact tape pieces out.

What about toxic gick that may be on the cardboard?  Research has shown the tremendous toxic remediation qualities of fungi.  Let the fungi eat it all up, if there are nasty things in or on the cardboard.

I really like this approach.  As far as toxic gick, any cardboard printed in Canada or the US (I think Mexico too) has to use vegetable ink.  I think Europe's the same, so most cardboard seems pretty benign.

Hi Chris,

Would one of those paper slicers like we had in art class work?

William Roan wrote:Hey Chris
You made me curious, so I dug 8 holes around the garden and I can’t find any cardboard logs. I may be looking in the wrong places, but they seem to have completely disappeared after a year and a half.
When I started I didn’t have access to dirt and what dirt there was, was scrapped off with an end loader. When the grounds people tried to get rid of the English ivy that had been growing in the garden plot,  for the last 30-40 years. All I was given was a large rock, with a layer of gravel and clay.
So for my needs the cardboard and grass clippings have turned into black mulch. If I were to do it again, I would put grass clippings and kitchen waste between each layer of cardboard.
All organic material is going to break down over time. When it does, start all over, knowing that you are enriching the earth.

As a friend in Arkansas said, “When hard times come, people think all they have to do is stick a few seeds into the ground and they will be able to feed themselves. It doesn’t work that way, you have to improve the soil first.”
Biologybill

Was looking into ways to turn massive amounts of cardboard into rich soil in a hurry. This oldie thread has some great ideas! I really like the log method. Faster to make cardboard logs than to slice boxes into 6” strips that fit in my cross cut shredder. I shred cardboard for my vermicompost bins and the red wigglers do a good job breaking it down, but I’ve got more compost than they can keep up with.

I’m thinking of turning the logs vertical and burying them to use them. I’ll layer the cardboard with grass clippings and soaked them in manure tea. I bet Seminole Pumpkins would do great in these.