Cardboard Mulch

How I started turning Amazon boxes into pretty mulch for my veggies.

I’m tired of wasted boxes

So my wife and I order too much online from Amazon, Walmart, etc. This is very much out of laziness and our shared dislike of shopping. I try to keep up, but regularly fill my recycling bin, get tired of breaking them down, etc.

I was trying to figure out a good way to somehow use all this paper waste in my vegetable garden. I know about Lasagna gardening, but that’s a slow cycle and I’m too lazy to prep that much.

I looked into using it in regular compost, and wandered into the exciting world of Vermiculture. OK, I’m too lazy for that too. But these people are using shredded cardboard all the time. They must have good ideas.

Sadly a lot are soaking and tearing. But I wandered into a few youtube videos of people using shredders on their cardboard and decided “what the heck”.

My shredder

I bought an ATIVA 12 sheet micro cut shredder. I think this is just OfficeDepotMax brand, and don’t specifically recommend it over another brand of the same thing. It lists at $159.00 which is a rip off, but I got it on sale for a more reasonable $99.00.

shredder

Here’s an image of the feed slot. It clearly shows warnings that look to mean

  1. Warning
  2. iBook
  3. No hands
  4. Don’t do business
  5. Don’t have children
  6. No ponytails
  7. No hairspray
  8. You can only shred shredder oil

I already have children and I’m shredding cardboard. Whoops.

Lessons I’ve learned

It tears through standard corregated cardboard, without straining. It struggles more with thicker non-corregated cardboard, like the box for a 12 pack of Coke. Anything thicker or denser than that, I’m not trying.

I cut the cardboard into strips 4-6 inches in width and generally try to feed the cardboard with the corregation going vertically, although I do it the other way plenty on weird pieces. It makes a little different sound that I don’t like as much. Science!

I do pull off excess tape. I have to be careful about where the boxes are glued together and make sure I don’t accidently feed double-thickness through it.

I do give it breaks after I fill the bin a couple times when I’m binge shredding.

It makes the most satisfying noise on crisp cardboard. But generally the experience is incredibly satisfying period. My children like to take turns “feeding” the shredder. My youngest has taken the metaphor so far as to call the bin its “belly” and yells that “its belly is full” when the sensor kicks in and stops the shredder. I enjoy this now, I’m sure it’ll be annoying eventually.

It will sometimes just make a mountain in the middle of the bin and not evenly fill it so it’ll kick off even though the bin is half full. Not a big deal.

I’ve shredded enough to cover 2 8x4 raised beds with 2-3 inches of mulch. so far plus the box shown below. I’ve sent the included oiling sheet through, and ordered a 40 pack of them from Amazon, of course.

The results

mulch mulch in hand

As you can see it makes beautiful little pellets of the cardboard. It’s super light and fluffy but heavy enough not to blow away easily.

I like that it’s light colored, because it won’t bake my roots here in zone 7. It holds water well, but not too well. It’ll break down pretty quickly with all that surface area.

Don’t follow this advice

According to the manufacturer, you should not shred cardboard of any kind. You should not shred tape. You should wait an hour after shredding for 8 straight minutes. You should oil the machine after 30 minutes of use. Failing any of these breaks the warranty and for me that ship sailed when I shredded the box it came in.

Other dumb stuff I do that I should point out:

  • I shred color printed cardboard. I have no idea whats in these inks or coatings. Probably both arsenic and old lace.
  • I shred Chinese cardboard. You know the kind with the weird mushy consistency. It may have heavy metals in it. Brutal.
  • I shred tape on boxes. I don’t know what’s in the tape or the adhesive. Probably horse hooves and fossils.