Wednesday, December 02, 2009

is paper safe for the compost pile?

Are there any toxins in the paper or the inks that should be a concern for gardeners?

This is the best reference I've found:
GardenWeb discussion

Also, lasagna gardeners use lots of paper and a nice "thread" is here.

I can't find any specific articles to cite but as far as I can tell, paper products are nutritious and safe for the compost pile.


Dan said...

I think all ink is safe now being it is touched so much. Now if that supposed safe ink came from china....

Jessica said...

I started lasagna gardening this fall, and the books I've read on the subject suggest that if you use newsprint, you use only black ink newspaper in the beds (Wall Street Journal is best b/c least colorful pages), because pigments in colored inks may contain heavy metals.

We don't subscribe to the WSJ, only the NY Times. But I tried to use only pages without color, and the newprint is only on the bottom layer of the raised bed as a weed barrier and doesn't get tilled up into the "open" compost.

The article at has interesting info on the subject and suggests testing food-gardening soil for heavy metals and contamination from other runoff (lead house paint, car exhaust, pavement runoff).

pjkobulnicky said...

I agree with Jessica ... I have always just put color supplements in the recycle bin and saved the black and white for the garden or the compost. My guess is that colored newsprint is all soy-based now but it is not worth wondering.

Nate Finch said...

I'm with the rest of them. Mrs Finch read up on it back when we got ours, and all the sources say to just make sure you use only paper with black ink. I don't really know that there's really anything too dangerous in even colored inks at this point... it's not like lead paint or anything.. but better safe than sorry.

kathy said...

OK. I will stick with the black ink only.

Ken said...

I think there might be some more fact and nuance needed in this discussion.

First off, in the past, I have used newspaper and cardboard as a mulch and newspaper for vermicomposting, and I have also looked for and haven't found much in terms of scientific reports on paper/cardboard composting (not just for the words "safe").

It's one thing to believe that the soy-based ink will decompose sufficiently such that it will benefit or at worst cause no effect at all on your crops (or you). However, I think it is important to state what is known.

"Soy-based" ink means it has soy oil as a main component (among other components). I think this term "soy-based" often make people feel better because it sounds good. But obviously none of us would compost paints labeled "water-based."

From wikipedia (and referenced from credible sources), 1) "soy ink is not edible or 100% biodegradable because the pigments and other additives that are mixed with the [soy] oil are the same as those used in petroleum-based inks, 2) ink from personal printers is not soy-based. This second point makes me question ink on paper other than newsprint (like junk mail, scrap paper from work, etc.). I was curious of your paper since your photo of shredded paper shows lots of color.

I, too, like GRIST, but let's still pull a few points from there: "Pigments themselves [in ink] still contain heavy metals..." "Although toxins are present in quite small amounts..." Umbra goes on to say her "sources" said it was safe for garden use. I'd like to see those sources. Like what exactly happens during composting to the adhesives that give cardboard its shape? And what about BPA, the plastic additive now commonly in the news, since it is linked to recycled paper, cardboard, and most significantly in cash register receipt paper. Something tells me these same sources have told us heating in and drinking from plastic containers is "safe," which I think requires more caution.

Without knowing for sure, using newsprint might be warranted simply because of conveniences. We still drive cars (to varying degrees) even though we know that promotes pollution. However, since leaves are abundant in most places, I now just collect those in the fall and store for later use.

Anarchy in the Garden said...

I toss all newspaper and paper shreds in the compost and call it a day!