Is dyed mulch safer for you, your children, your pets, and the environment than is natural organic mulch? It’s pretty – no doubt about that. But as one of my grandchildren says, it’s complicated.
The complicated history of dyed mulch
In the last several decades, dyed mulch has become the rage in many suburban homes. These mulches were made by grinding up wooden pallets, old decks, wooden fences, and other processed wood materials. They are then dyed in different colors. But dyed mulch has a disturbing and checkered past.
Before 2003, all “outside” lumber (decks, wooden pallets, playgrounds, fences, and, in some cases, homes) producers used wood treated with CCA or Chromated Copper Arsenate. Researchers were finding patterns of health problems associated with CCA, including headaches, diarrhea, and nausea. They also found that there are more life-threatening problems. These include liver and kidney damage, gastrointestinal problems, hypotension, coughs, renal failure, delirium, encephalopathy, seizures, and various other serious illnesses.
Some mulching and composting companies also used utility poles, railroad ties, fence posts, and other creosote-preserved materials, which are carcinogenic.
EPA bans CCA, but the hits just keep coming
In 2003, the EPA banned the use of CCA as a wood preservative. In 2005, it prohibited the use of creosote-treated products. But that’s not the end of the story.
No new wood products can contain CCA or creosote, there were, and still are, millions (perhaps billions) of free pre-EPA ban out there. Millions of wooden shipping pallets, decks, utility poles, and other wood products treated before the ban. And there is no ban on using this wood as mulch.
The process for making dyed mulch
Most responsible mulch manufacturers use natural products, e.g., trees, branches, grass clippings, shrub trimmings, to make their mulch. The manufacturer grounds up the raw material, ages it, and then sells it to the public.
However, some mulch producers, faced with an abundance of pre-2003 wood, decided to do what they had been doing. That is, making mulch from these same CCA products. Dyeing these products kills two birds. The manufacturer can use cheap or free CCA-treated wood, dye it to cover up the fact, and sell it for as much or more than natural organic mulch. Since there is no law banning the use of CCA-treated lumber as mulch, it is perfectly legal (but not ethical) to do so. These companies are not required to disclose the origin of their mulch.
Harmless or not?
Much of the dyes used today may appear to be somewhat harmless, like iron oxide-based dyes for shades of red and brown or carbon-based pigments for black and dark brown. However, there are some health consequences for them as well. some manufacturers use cheap dyes laced with harmful or toxic chemicals. Follow the adage: if the deal sounds too good to be true, it probably is. And there’s more.
Dyed mulch and its effect on the soil
There are some common properties of all dyed mulches, whether or not they are from CCA-treated wood. While natural, non-dyed mulches break down and add their nutrients to the soil, dyed mulch takes a long time to break down.
While it keeps the soil at a stable temperature, colored mulch in gardens can rob plants of nitrogen needed to survive. Dyed mulches can also kill beneficial soil micro-and macro-organisms.
Less critical but of interest is that certain fungi are attracted to dyed mulch. These fungi can transfer to the sides of houses and other structures. It is unsightly and hard to remove.
Many think that hydrophobia describes rabid animals (or people). Hydrophobia can also be used to express some mulches. Dyed mulches also can be hydrophobic. When they dry out, they do not absorb water easily. The plants they are supposed to be protecting dry out, become stressed, and often die. Plus, since the water has no place to go, it just slides off the top of the mulch and goes on to erode soil elsewhere, in addition to carrying potentially harmful elements into streams, waterways, and eventually into the Gulf.
Don’t get me wrong. There are some decent-dyed mulch producers. But I would rather be safe than sorry.
To find a natural organic mulching facility near you, go to findacomposter.com. The New Materials Institute at the University of Georgia, The Biodegradable Products Institute, and BioCycle are the three entities that oversee the Find a Composter.
And there are natural organic mulches that you can buy in 40-50-pound bags from nurseries and big box stores. Just look for the OMRI (Organic Materials Review Institute) symbol on the package.