Homesteading, Gardening, and Off-Grid Living

The Pros and Cons of Dyed Black Mulch Vs Natural Mulch

By: Zac Friedman

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Dyed black mulch is one of the most attractive mulches. It has a modern look that really makes your plants stand out. It can also suppress weed growth, insulate the soil, retain soil moisture, and reduce soil erosion. There are some drawbacks to consider. Black mulch can absorb quite a bit of heat. It can also release potentially harmful dyes and other chemicals into the soil. This guide outlines the pros and cons of black mulch to help you decide whether or not it’s the right choice for your garden beds. 

Black Mulch For Landscaping: Pros and Cons

What is Black Mulch?

Generally, black mulch refers to wood mulch that has been dyed black. It can also refer to black colored inorganic mulch such as black rock, black landscape fabric, or black rubber mulch. Black mulch can work well in gardens, walkways, and any other outdoor space.

This guide focuses on black wood mulch. Black wood mulch is often made from recycled wood or waste wood, usually from pine trees. It is then dyed black using carbon-based dyes to make it appear more attractive and consistent. Bark mulch can also be black.

Black rubber mulch is often made from old tires that have been shredded. Black landscape fabric is made from a type of black woven synthetic material. Rock mulch can also be black. The most common type is lava rock. River rock and pea gravel also come in black. 

black lava rock mulch
Black lava rock mulch

Pros of Black Mulch

  • It’s attractive- The main reason people use black mulch is because it is aesthetically pleasing. The black color really makes green plants and colorful flowers pop. It can give your flower garden a modern look. It also contrasts nicely with grass. Black goes well with most home colors as well. Black mulch is a great way to enhance the curb appeal of your home. Dyed mulch comes in various colors. Black and red are the most common. 
  • Black mulch absorbs heat- This can be both a positive and a negative. The benefit is that black mulch can help keep the soil temperature warmer in cooler climates. This is because dark colors absorb heat from the sun. This heat helps keep the soil warmer. This can extend the growing season slightly. The ground won’t freeze as quickly when the weather starts getting cooler. If you live in a hot climate, this can be a negative. 
  • Weed control- Black mulch acts as a weed barrier. It blocks weed seeds that blow in or get dropped by birds from reaching the soil. It also blocks the sunlight from the soil so existing weed seeds have a harder time germinating and growing. Some weeds will still grow but you won’t have to weed as much when you mulch. 
  • Moisture retention- Black mulch helps the soil stay moist longer by reducing evaporation. The mulch shades the soil and blocks the wind. This helps with water conservation. You won’t have to water as frequently. You’ll save money on your water bill as well.
  • It’s widely available- Black mulch is popular. You can find it at your local garden center. You can buy it by the yard and have it delivered or buy it in bags. 
  • It’s long lasting- Dyed mulches decompose slower than other types of mulch because they are treated. The treatment slows down the decomposition process. Black dyed mulch also tends to last longer than other types of dyed mulch. The black color doesn’t fade as fast. The wood will break down over time. On average, you can expect black mulch to last around 2-4 years before you need to add a fresh layer of mulch. Exactly how long it will last depends on the climate where you live. 
  • It reduces erosion- Black mulch blocks the impact of heavy rain on the soil surface. It can also absorb some moisture. This helps prevent soil and nutrients from getting washed away during heavy rains.
  • Fewer pests- The treatment and dye process kills any insect eggs that could be on the mulch. You don’t have to worry about introducing pests to your yard. Dyed black mulch is also less likely to attract pests such as termites, ants, and rodents. 
  • Black mulch is unlikely to be contaminated with fungi or diseases- Most black mulch is kiln-dried. It is then dyed. This process kills off any bacteria or fungal spores. You don’t have to worry as much about introducing disease to your garden. 
  • It adds nutrients to the soil- Dyed black mulch is made from wood. As bacteria and other decomposers break the mulch down, some nutrients are released into the soil. This improves soil fertility. Organic matter is also added to the soil. This improves the soil quality. 
  • Low maintenance- Dyed black mulch doesn’t require much maintenance after you apply it. You may have to do a bit of weeding once in a while. It will degrade over time. You may need to apply fresh mulch every 2-4 years to keep it looking good. 

Cons of Black Mulch

  • It can be expensive- Dyed mulch is more expensive than regular brown mulch. The treatment process adds to the cost. On average, black mulch costs $30-$50 per cubic yard, depending on where you live and the quality of black mulch you buy. If you have a large area to mulch, the cost can add up. There are many cheaper or even free mulch mulches available. If you’re on a tight budget, black mulch isn’t the best option. Instead, consider pine needles, grass clippings, or shredded leaves.
  • Heat absorption- Black mulch absorbs a lot of heat due to the dark color. Some of this heat can transfer into the soil. Having a soil temperature that is too high can be really hard on plants. It can overheat their roots. In hot climates, this could kill heat sensitive plants. The heat can also radiate up into your yard. It can even heat up your house. This can make your home less comfortable if it’s too hot. 
  • Black mulch can release chemicals into your soil- Dyed mulch can contain a number of potentially harmful chemicals that can end up in your soil as the mulch degrades. The mulch will contain dyes. The dyes used for mulch are supposed to be non-toxic but that’s not always the case. If you’re an organic gardener, you won’t want these chemicals in your vegetable gardens. If your mulch was sourced from recycled wood, it could contain toxic chemicals like creosote or chromated copper arsenate (CCA). These chemicals were used to treat wood in the past. Sometimes wood from demolitions can contain them. Sometimes wood is sourced from old pallets. These can be treated with a chemical called methyl bromide, which is a pesticide. These chemicals can kill beneficial bacteria, earthworms, and beneficial insects. Over time, this can kill your soil and make it less fertile. You don’t have to worry about this with organic mulches. 
  • It doesn’t add many nutrients to the soil- One of the main reasons people mulch is to improve soil fertility by adding nutrients. Black mulch will add some nutrients as it degrades but the amount is pretty negligible. This is because the treated mulch degrades slowly. It also doesn’t contain as many nutrients as other types of mulch such as compost.
  • It’s made from low-quality wood- Most dyed black mulch is made from trash wood. It’s usually made from old pallets, old decking, or old lumber that was used in buildings that were demolished. After the wood is chipped up, it is dyed to make the color consistent. The dyes are supposedly organic. This old wood could have been treated with CCAs or other toxic wood treatments. Most manufacturers either won’t tell you where the wood came from or they have no idea. There is no way of knowing what kinds of treatments the wood has on them. 
  • The dye can get on your hands- While you’re handling the mulch, you may notice some of the dye rubbing off on your hands. You will want to wear gloves while applying it to avoid this. 
  • The dye can run- When it rains, some of the dye can run off onto your sidewalk or driveway and cause staining. It can be removed but it will take some scrubbing. This is common when the mulch is fresh. 
  • The color will fade over time- Some of the dye will wash away over time. The sun will also bleach the wood. The color will fade. Dyed black mulch won’t always stay black. It will become a bit more gray as it ages. Exactly how fast it will fade depends on whether or not it’s in direct sunlight, the climate, and the quality of mulch you bought. 
  • You can’t compost it- It’s best not to compost black mulch because of the dye. You won’t want that in your compost or in your garden. It will also break down slowly because it is usually treated. When it starts to fade or break down, you’ll need to remove the mulch and dispose of it. You may have to haul it to your local waste management facility. Yard waste facilities usually won’t take dyed mulch. This makes black mulch harder to get rid of. It may cost you some money to dispose of it.
  • It’s not environmentally friendly- The dye makes black mulch less environmentally friendly than other types of mulch. It is not a completely natural material. It contains chemical dyes and potentially other chemical treatments. It’s best not to contaminate your soil with chemicals, even though they may be non-toxic. Even after the mulch breaks down, these chemicals can stay in your soil for many years. 
  • It may not be suitable for dogs- Dogs can sometimes chew on wood chips. This could be harmful to your dog if your black mulch was treated with some type of chemical. The dye probably isn’t good for them either. Rubber mulch can be a choking hazard for dogs. If your dog tends to chew on sticks or wood, consider going with an organic mulch that is undyed or black landscape fabric. 
  • Nitrogen depletion can be an issue- Decomposers in the soil have to work hard to break the black mulch down. They use nitrogen to fuel their activity. This removes nitrogen from the soil, which can cause a nitrogen deficiency in your plants. If you notice yellowing of your plants leaves, this may be the issue. It’s a good idea to use some nitrogen rich fertilizer with black mulch to prevent this.  
  • It’s not ideal for your vegetable garden or around fruit trees Dyed black mulch and black rubber mulch should not be used around food that you’re growing. Chemicals from the mulch can leach into the soil. The vegetable plants can absorb these chemicals through their roots. This can slow plant growth. These chemicals can also end up in your food in some cases. You can use black plastic sheeting around vegetable plants. It can be used to suppress weeds and retain moisture in the soil. 
  • It could be a fire hazard- All wood mulches are flammable. Particularly when they get dry during the hot summer months. They can absorb heat and dry out quickly. Dry mulch can catch fire easily. Rubber mulch is also flammable. It burns hot and it can be hard to put out after it catches fire. If you live in an area where wildfires are common, it’s best to avoid these mulches around your home. Black landscape fabric can also burn but it’s not as flammable as other types of black mulch. 
  • Black mulch may not match your home’s aesthetic- Black doesn’t go with all homes. The black color can also look a little bit unnatural. Sometimes the black is too dark. Black plastic mulch can get torn easily and become an eyesore. Rubber mulch just doesn’t look natural. It is obviously artificial. Some people don’t like the look of these black mulches. They prefer a more natural aesthetic. 
Black lava rock mulch

My Experience

I used to use black mulch in my front yard. It looked great in my flower garden. It really made my house stand out. I stopped using it because I didn’t like the idea of the dye ending up in my soil.

These days, I only use organic mulch that is undyed. I want to keep my soil in as good of condition as possible. I also prefer the look of natural mulch. It looks less artificial. I prefer a natural color. I’m a fan of cedar mulch. In my vegetable gardens in my backyard, I often use a free mulch like grass clippings, shredded leaves, or pine straw (pine needles).

Black mulch offers most of the benefits of any other type of mulch. It helps keep the weeds down, retain moisture, and reduce erosion. It’s also a common mulch and it lasts a long time. It degrades slowly so you don’t have to replace it frequently. 

There are some drawbacks to consider before you apply it. Black mulch can contain chemicals and dyes that aren’t great for your soil. It can also cause the soil to overheat because the dark color absorbs a lot of heat from the sun. Black mulch also doesn’t add many nutrients to the soil. It is also more pricey than other mulches as well.

Black mulch isn’t the best mulch for every garden but it can be an excellent choice in some cases. It really comes down to the type of garden you have and your personal preference. Whether or not you choose to use black mulch in your flower beds, I hope this guide has helped you in making your decision. 

Do you use black mulch in your garden? Share your experience in the comments below!

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Black Mulch For Landscaping: Pros and Cons

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