Black mulch, doesn’t get the same press as other types of mulches you can use in and around your garden, does it? Well, that’s a shame because black mulch actually has a lot of benefits… as well as some cons. Really, it’s all about personal choice, so it’s best to make your own decision and ultimately see if the benefits outweigh the drawbacks. In this article, I am going to discuss the pros and cons of using black mulch and summarise it the best I can:
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Pros and cons of black mulch
So apart from aesthetic reasons, there are quite a few different advantages of using black mulch. For example, it is great at suppressing weeds. The darker the colour, the better it is at blocking out sunlight which suppresses weed growth. Let’s name a few:
- It stifles weed growth in the areas you have laid black mulch
- Retains moisture
- Can add nutrients to the soil when it breaks down
- Makes a garden space look tidy and well looked after
- Can be too hot for plants to grow
- Can release poisonous chemicals
Pros of Black Mulch
There are surprisingly quite a few advantages to using black mulch. Although it isn’t a naturally occurring product, it does have some benefits over other types of mulch:
Stifles Weed Growth
The main advantage of black mulch is that it helps to stop weeds from growing where your other shrubs may be. This is because the black colour blocks out sunlight, which suppresses weed growth. Weeds can be a real annoyance in any vegetable garden, so if you are looking for a way to reduce the amount of weeding you have to do, black mulch is a great option.
Helps Soil Cool and Retain Moisture
Another big advantage of black mulch is that it helps your soil retain moisture. This is especially beneficial in the summer months when the sun can quickly dry out your soil.
Makes You Garden Look Neat and Manicured
If you are looking for a way to make your garden look tidier and more well-kept, black mulch is a great option. The dark colour creates a sharp contrast with the green of your plants, which can really make your garden stand out. Additionally, black mulch can help to hide any bare patches in your garden that may be difficult to fill in.
Adds Nutrients to Soil When it Decomposes
Another big advantage of black mulch is that it actually adds nutrients to your soil as it decomposes. This is because the mulch is made from wood chippings, which are a good source of nutrients for plant growth. As the colored mulch breaks down, it releases these nutrients into the soil, which can help to improve the health of your plants.
Cons of Black Mulch
So you guessed it, there are quite a few disadvantages of black mulch as well. Here are some of the main ones:
The wood may have been chemically treated
The wood may have been treated with creosote or chromated copper arsenate. Since early 2001/2002, these substances have been illegal, but it persists in any wood that was treated before this time. This means that black mulch may be made from wood that has been treated with chemicals, which can be harmful to your plants and the ecosystem. If you do decide that black mulch is necessary for your garden, then choose one that has been certified by the Mulch and Soil Council.
Not good for the environment
You can’t recycle black mulch to be reused. The pigments used to dye black mulch can be harmful to the environment. These pigments can leach into the soil and contaminate groundwater. Additionally, when the mulch decomposes, the pigments can also be released into the air, which can damage plant life. For these reasons, you have to dispose of the recycled wood at your local waste management facility.
The black colour will fade over time
Although black mulch looks great when it is first applied, the colour will eventually start to fade. This is because the pigment that is used to dye the mulch is not UV stable, which means it will break down when exposed to sunlight. As a result, you will need to reapply the mulch every year or so in order to maintain its colour.
Temperature can be too high for plants
The ground beneath the black mulch appears to be hotter. The plants wilt faster and demonstrate greater symptoms of heat stress. The extra heat is due to the colour black absorbing more of the sun’s rays. The raised soil temperature can also make it difficult for young plants and seeds to germinate.
Can be a good home for pests
The darkness of black mulch can provide a good hiding place for pests, such as slugs and snails. These pests can then come out at night and feed on your plants. If you have a problem with garden pests, then black mulch may not be the best option for you.
Another disadvantage of black mulch is that it may produce poisons in the soil. The answer is quite simple – the longer a decomposition period, the more likely it is to produce toxic material and other undesirable things. As a result, before laying your black mulch, you should put a piece of plastic on top of the ground.
Can be a fire risk
Another disadvantage of black mulch is that it can be a fire risk. This is because the wood chips that are used to make black mulch are highly flammable. Technically, black mulch is no more flammable than any other mulch. If you live in an area that is prone to wildfires, then black mulch may not be the best option for you.
It Can Be Messy
One of the big disadvantages of black mulch is that it can be quite messy. This is because the dark colour can easily show up any dirt or debris that gets on it. Additionally, the small pieces of wood can be easily tracked into your house if you are not careful with children or pets.
Alternatives to Black Mulch
If you are concerned about the disadvantages of black mulch, then there are a few alternatives that you can use. These include:
Premium shredded bark mulch
This is great stuff to work with in all honesty. Usually, when I first receive it – it’s partially decomposed (the stuff is quite hot when I first have it delivered) and fully decomposes in about a year to 18 months. Earthworms and other aerating insects LOVE this stuff. I find that it keeps my pH stable and provides a good environment for beneficial bacteria to grow and decomposers such as mushrooms and fungi.
Ornamental Cocoa Mulch
This stuff is pricey and doesn’t last long, but it builds soil and adds organic matter. I usually have to apply twice a year to maintain a decent weed barrier, making this yet more costly. However, I love the stuff and it does smell like chocolate (considering it’s made out of the shells of cocoa beans) every time I water it!
This is a fantastic alternative to black mulch, but it can be quite difficult to find. Mushroom compost is the by-product of mushroom farming and it is an excellent source of nutrients for your plants. It also helps to improve the drainage and aeration of your soil.
Pine needles make an excellent mulch for acid-loving plants such as rhododendrons and azaleas. They are also great for suppressing weeds and keeping the soil moist. Cedar Mulch is also a very good alternative which I have written an article about
This article discusses the pros and cons of black mulch. Black mulch has several disadvantages, including that it is not UV stable, can be a fire risk and can be messy. However, it also has some benefits, such as that it is good for the soil and can help to suppress weeds. So let’s summarise:
- Black Mulch stops weeds from growing as quickly as it shades the ground
- Makes your garden look more aesthetically pleasing
- Adds nutrients to the soil when it decomposes
- Black Mulch is usually chemically treated
- You can recycle Black Mulch
- The black colour dye will fade over time
- The temperature can be too high for plants to grow properly
- Can encourage pests
- Breeds toxins
- You run the risk of fires developing
- It can be messy
- Alternatives to Black Mulch are Shredded Bark Mulch, Ornamental Cocoa Mulch, Mushroom Compost and Pine Needles