There is an ongoing debate in the agricultural world concerning the safety, or lack thereof, of newspaper use in a garden. Newspaper has been used widely in vegetable gardens as a mulch, as a natural weed killer, and even as potting cups.
Newspaper is a biodegradable substance. The Nuffield Foundation, which focuses on science and social science, conducted an experiment with its students which demonstrated how microbes in the soil break down materials. In short, soil microbes contain enzymes that break down cellulose. Since paper is made from wood, and therefore is composed greatly of cellulose, soil microbes easily break down and digest paper. During this process, carbon is released into the soil. Carbon is an essential element to healthy soil. You can read more about the experiment, and how microbes digest these materials here: https://www.nuffieldfoundation.org/practical-biology/microbes-ate-my-homework
Despite wide use of the material, many questions have been raised about the possible environmental threats it can pose. Are the inks toxic? The glues? What about color inks versus black inks?
What about those lovely glossy pages? The fact is that there is a lot of information out there, some true and some untrue, and in the end it will all depend on personal preference.
Nevertheless, here are the common questions and facts related to the debate.
First and foremost, is the ink toxic? In the past, newspaper ink was largely composed of heavy metals such as lead, and other toxic materials like cadmium. However, because of the toxicity of these materials the Newspaper Association of America began searching for safer bases for newspaper inks. After lengthy studies and trials, soybean oil was found as the solution. Not only is soy ink more environmentally friendly, but it also makes for more accurate colors. Soy ink is also lower in Volatile Organic Compounds, which decreases toxic emissions during the printing process. Today, the majority of newspaper print is composed of soy ink.
Though soybean oil is a much safer alternative to toxic heavy metals, organic farmers have now faced the question of GM use in the soybeans used for this oil. Since GMO use is widespread and undesirable to organic farmers due to its carcinogenic effects, this adds a questionable bullet point to the debate, one that is unfortunately shrouded in uncertainty.
Another issue to consider is the manner in which the pulp is bleached. A common method for the whitening of pulp is, obviously, using chlorine bleach. As chlorine breaks down in the environment, it leaves behind dioxins that accumulate over time. The breakdown of these byproducts is slow, and though its impacts in soil are trace, it is still a concern. The good news is that most newspaper pulp is bleached with hydrogen peroxide which has more benign effects on the environment.
With all of these questions and issues in mind, the National Center for Appropriate Technology mandated the ATTRA, or Appropriate Technology Transfer for Rural Areas which specifically targets sustainable agriculture issues. The ATTRA has set guidelines for organic farmers regarding what materials can be used in the soil as a compost additive. The Organic Materials Compliance guideline outlines the basic steps to compliance with organic standards.
In short, it states “Regarding the use of newspaper and cardboard, both can be useful materials used in organic crop production for suppressing weeds, retaining moisture and adding organic matter to your soil. NOP regulations allow the use of newspaper or other recycled paper as an ‘allowed synthetic’ with the provision that it be ‘without glossy or colored inks’”
The guideline also touches lightly on the use of cardboard and the affects that the glues may have. Here, it states “A few years ago, ATTRA did research on the different substances that go into making cardboard, as well as the glues, inks, and coatings that may be used. Based on the information available then, the basic components of corrugated cardboard seemed to be relatively benign.”
So, the issue of whether or not to use newspaper in your garden all comes down to a personal choice. You can contact your local newspaper and ask if they use soy ink, and how their pulp is bleached. Keep in mind the positive research and studies that have been conducted with this issue. All in all, newspaper has proven to be a safe, handy tool in the garden.