Most red or black mulch is made from recycled wood, and the colors come from mineral dyes. The vibrant colors provide a lovely contrast to greenery and neutral home colors. Unfortunately, the base materials could carry certain risks, but there are also strategies to using dyed mulches safely.
In this article, you’ll learn about the dyes and wood products used to produce colored mulch. We’ll also look at ways to choose safe colored mulch options and proper usage tips.
Most mulch producers use these compounds to add vibrant red or black color:
Red mulch: Iron oxide
Black mulch: Carbon-based colorants
It’s a common misconception that the dyes used to create colored mulch are to blame for any potential toxicity. But in reality, there’s no evidence that the dyes commonly used for red or black mulch have any negative effects.
Here are the details.
Iron oxide is essentially rust. It’s derived from iron that has undergone the oxidation process from air exposure.
Iron is an essential nutrient that enables plants to produce chlorophyll and process oxygen. As red mulch decomposes, iron oxide enters your soil and may help encourage plant growth.
Carbon-based colorants are organic dyes made from carbon molecules or atoms.
Aside from their use in colored mulch, these dyes are also present in several common household items:
The Dangers in Wood
According to the University of Massachusetts Center for Agriculture, Food and the Environment, the wood itself is where the chance for danger comes in.
Many mulch manufacturers produce black and red mulch from recycled wood products. Old wood typically has a dry, porous surface that readily accepts dye.
These materials could include:
- Shipping pallets
- Discarded construction materials
- Sawmill by-products
The concept of recycling wood into mulch seems like a great idea. Unfortunately, some of these materials could harbor dangerous substances. The biggest concerns are:
- Chromated copper arsenate
- Chemical residues
Let’s take a closer look at why these two substances could be cause for concern.
Chromated Copper Arsenate
Chromated copper arsenate (CCA) is a form of the poisonous element arsenic.
Manufacturers used CCA in the production of pressure-treated wood from the 1940s until the year 2003. Most of these CCA-contaminated wood products should be out circulation by now. Nevertheless, there is still a risk that colored mulch could contain old CCA wood.
Some dyed mulches contain pieces of retired shipping pallets. These pallets themselves may be free of CCA. However, they may have carried hazardous chemicals or been otherwise exposed to toxins in the past.
In much the same way that old wood absorbs dye, it can also easily absorb chemicals.
Staying Safe With Red Or Black Mulch
So do these potential dangers mean you need to avoid red or black mulch like the plague?
Keep in mind that not all dyed mulch contains contaminants. What’s more, the risks should continue to drop as fewer pieces of CCA-treated lumber are in existence.
Below are 3 tips to brighten your landscape in the safest way possible.
1. Spend Time in Research
Lumber from these sources carry the highest risk for CCA:
- Home renovations or demolitions
- Torn-down decks
- Other construction by-products
If possible, choose a brand that doesn’t use this type of recycled wood. You may need to contact the manufacturer with your questions.
Note: Even if the mulch supplier doesn’t use recycled construction materials, they may still use shipping pallets. It’s extremely unlikely that you’ll be able to find out the pallets’ history of chemical shipments.
2. Wear Gloves
Avoid touching red or black mulch with your bare hands when applying it.
Wear a pair of sturdy work gloves, and make sure to wash well when you’ve finished the job.
3. Don't Use Red or Black Mulch in Play Areas
Benefits of Red or Black Mulch
We’ve spent quite a bit of time talking about the concerning aspects of dyed mulch. But red and black mulch both have a few benefits to offer:
When you’re looking for a high-contrast finish against greenery or your home’s exterior, colored mulch delivers unparalleled results.
Red mulch looks particularly nice against white, gray or other neutral home colors.
And black mulch adds a dramatic touch that won’t clash with any shade of siding or trim.
Because the wood base is primarily made of salvaged material, dyed mulch is often at the lowest end of the price scale.
And when you’ve got a large area to mulch and budget constraints to keep in mind, that’s an attractive feature.
Easy to Find
Pretty much any home improvement store, garden supply store or nursery has colored mulch for sale all growing season long. Where I live, even gas stations sell dyed mulch during the summer!
All that to say, you’ll likely never have to struggle to find red or black mulch when you want it.
Recycles Old Material
If you don’t like the idea of using new wood in mulch, the fact that colored options repurpose existing wood material can be appealing.
What About Brown Mulch?
Brown is another common mulch color you’ll see. It has a much more natural look than the obviously dyed red and black options, and it looks great against home colors of almost any hue.
Just as with red or black mulch, the brown dyes are naturally-sources, often from organic materials. These materials may break down a bit more quickly than the other colors.
But the fading can also look a lot more natural and less off-putting than faded red-orange or gray.
Here again, like the other colored mulches, it’s the recycled wood that can raise the red flag with brown mulch. The wood sources are typically the same (pallets, construction leftovers, etc), so you should still use caution when using brown-dyed mulch.
Frequently Asked Questions about Red and Black Mulch
Colored mulch could contain dangerous substances, like arsenic or industrial chemical residues.
Whether your dog chews on a piece of mulch or licks their paws after digging in it, they could get exposed. And due to their smaller size, your dog could be at higher risk for ill effects from chemical ingestion.
Consider putting up protective fencing around areas that contain red or black mulch. Not only will your dog stay safer, but your mulch can stay in better condition, too.
Of all the wood mulch options out there, dyed black mulch is likely to retain its original color the longest.
However, after a year or two, you’ll probably start to notice that deep black start to take on a weathered gray hue.
All dyed wood mulches, including black and red, are made from materials that may contain harmful substances. Because of this, it’s best to play it safe and keep red or black mulch out of any area where you grow edible plants.
Instead, consider using compost as mulch to grow healthy, safe fruits and vegetables.
For more tips on how to use mulch in your garden or landscape, visit our Mulch Mastery guide.
Red or black mulch protects plants, shrubs and trees while adding an instant pop of color to your landscape.
However, dyed mulch can harbor some dangerous elements. While there can be appropriate uses for red or black mulch, you’ll need to plan thoughtfully and use extra care.