concerns with using cardboard/newspaper as a mulch

paul wheaton wrote: I understand that in the permaculture world I am in the minority on this one.  Most permaculture folks are not concerned (including Sepp Holzer, Bill Mollison and Paul Stamets).

I've often wondered why they aren't more concerned. I've even asked an organic farmer who felt it was okay. I might use it for landscaping but not in a food garden.

A timely revival of this thread!

It is probably worth bringing up that the widespread finding of PFAS in toilet paper is likely the canary in the coal mine indicating that the recycled paper pulp stream is heavily contaminated. Paper-based food packaging often contains PFAS to prevent grease and liquids seeping through -- when these items enter the paper pulp stream, they are adding to the base load.

The litany of potential negative health effects from consuming PFAS is considerable, and this could be a reason to stop using cardboard in the garden -- particularly pizza boxes, but possibly other types as well.

I do personally use cardboard even so, but as a single application to suppress some of the extremely aggressive grasses we have here while establishing garden paths (not in the main garden beds themselves). I also make sure to never use color-printed cardboard, as the inks are still soy-based, but the pigments often contain lead (white, red, green), mercury (red), cadmium (red, yellow) and copper (blue, green) -- only black ink is relatively safe. Given that cardboard is a recycled material, it will have some quantity of these heavy metals from its recycled post-consumer portion. Use with caution!

I totally agree that cardboard, and newspapers are not a really great mulch. Not only there is glue and other icky stuff in there, nowadays, there are also PFAS in some of these water resistant products. I will keep asking for a complete BAN on PFAS.

I'm a bit suspicious of cardboard because I did a couple of years in a big box distribution center. The chemical smells that came out of some of those tailors, having just arrived from China, was often to put it mildly, a bit off-putting. Not to mention the chemicals used in case something alive was discovered on opening and it was sealed back up and fumigated.

Even though some, maybe most of it is probably fine, the amount I allow in my garden is, none.

If you have stopped using cardboard, have you found something that works as sheet mulch? I’ve been using it to smother grass.

This article just came out.

cardboard-does-not-belong-on-your-soil-period/

May Lotito wrote:This article just came out.

cardboard-does-not-belong-on-your-soil-period/

Thanks, May. This article is indeed extremely informative and I noted especially the inset table about PFAS and PFOAS and other bad stuff I've never heard of. I was planning to suppress weeds before installing some winecap mushrooms a a couple of beds this spring. I won't be using cardboard, that's for sure. I think I'm back to the conventional weeding for them.
I have become very interested in these "forever chemicals" since studying water in our County. Right now, our legislators are debating... and debating... and debating how to best remedy the soil once it is contaminated. The best analogy I can think of is that they are like unruly kids in a flooded house arguing about who is going to grab the mop, and I'm yelling: "FIRST, TURN OFF THE WATER, YOU IDIOTS!".
All these chemicals should be banned, period, full stop. There is so much convenience and money in continuing to use them that it will be extremely difficult to put a stop to them, but we must try. Presently, we all use items in our everyday life that contain PFAS without knowing. A person has to be extremely savvy to avoid them because since the 1940s, they have been in use and are now ubiquitous. As is, most of us  have some in our bodies:
"PFAS are known as “forever chemicals” because once released into the environment they do not break down and they can build up in the body. The Centers for Disease Control and Prevention has detected PFAS in the blood of 99 percent of Americans, including newborn babies. "
https://www.ewg.org/news-insights/news-release/2023/11/new-epa-data-show-millions-more-have-forever-chemicals-drinking#:~:text=PFAS%20are%20known%20as%20%E2%80%9Cforever,of%20Americans%2C%20including%20newborn%20babies.

Bethany Brown wrote:If you have stopped using cardboard, have you found something that works as sheet mulch? I’ve been using it to smother grass.

I haven't stopped using cardboard/newspaper because I never started using those.

Organic matter placed 6 to 12 inches will smother grass.  12 inches is best.

Some organic matter would be wood chips, leaves, coffee grounds, compost or even soil.

Also discussed here https://permies.com/t/18887/paper-poisoning-permaculture-produce-soil

I very recently gave in briefly and used some cardboard and feed sacks in one small area for bermuda grass and never felt good about it...after decades of not using cardboard and paper in our gardens I  look at that area as contaminated

We mostly try to keep things growing everywhere or covered in a mulch.