Guide to — Types of Mulch
Mulch is probably the most talked about subject among gardeners when they meet. The fact that there are a number of types of mulch is the reason why mulch continues to be debated and talked about. As can be expected, each individual has his/her own preference. Others just like to use a combination of different types of mulch.
Different types of mulch are suited for different climates. That is why people choose to alternate between the different types.
Before we get started on the different types of mulch, let us take a look at what mulch is.
What is Mulch?
The word ‘Mulch’ has its roots in a German. It comes from the word ‘molsch’ which means ‘beginning to decay’. This is probably used in reference to the first types of mulch that were biodegradable. That brings us to what mulch is.
If you thread through a path in the forest, you will notice that there are a number of layers of leaves and twigs that crunch under your foot as you walk. This layer gets thicker or thinner depending on the season. In fact, this is nature’s way of providing its forests with mulch.
Mulch is a thin layer of any substance that is spread over the soil. It is used to mimic the conditions that one sees in the forest. This is because mulch has a number of virtues that are very useful.
Benefits of Mulch
Mulch has many properties that have made it popular among the gardener committees. Let’s take a look at what makes mulch so special!
Video | Mulch Benefits
- Conservation of moisture: A lot of gardeners spend a lot of time watering their gardens. A lot of this water is lost to the surrounding air because of the difference in temperatures. Mulch forms a barrier between the wet cool earth and the hot atmospheric air. This helps the soil retain its moisture content!
- Protection against weeds: Since the mulch forms a protective layer between the sun and the soil, weeds find it very hard to sprout and grow. Even if the weeds manage to sprout, the lack of sunlight causes them to wither and die.
- Winter protection: Mulch doesn’t stop the ground from freezing. During the freeze and thaw cycles, plants find themselves being thrown out of the ground. Mulch prevents this from happening.
- Improves the fertility of the soil: The organic types of mulch decay over time and slowly add to the nutrients in the soil. In addition to this, it also encourages the growth of worms. The movement of these worms helps transport the decomposing matter deeper into the soil!
- Prevents soil crusting: Soil crusting occurs when a water droplet strikes the ground with force. This force of impact causes the soil particles to spray in all different directions. This causes soil crusting. Now this ordinarily shouldn’t be a problem but every gardener knows that soil crusting means that the ground absorbs water more slowly. Mulch on the other hand breaks the force of impact. The water then trickles through it and soaks into the ground.
- The aesthetic perspective: Mulch gives the ground an even and filled out look. The protection against weeds is another reason why it improves the aesthetics. Some inorganic methods of mulching (like stone) can be used in designs that look very trendy.
Types of Mulch
The basic differentiation between the different types of mulch is based on whether they are organic or inorganic. Organic mulches are those mulches which decay and add to the nutrient quality of the soil. These mulches are similar to the mulch that the forest provides its floor with. Inorganic mulches on the other hand do not decay. They however have their own set of advantages.
Video | Different Types of Mulch
Organic Mulch
There are a large variety of different items that are being used as organic mulches. These types of mulch are preferred because they inhibit weeds and conserve water. Unlike inorganic mulches they add to nutritional content of the soil while also encouraging the growth of worms and microorganisms.
Let’s take a look at the different types of organic mulches and the virtues of each of them.
— Bark Mulch
This type of mulch actually is composed of two types. It can be divided based on whether hardwood or softwood is used as the mulch.
Shredded hardwood that is used as mulch is a byproduct from industries that manufacture paper. It can also be traced to lumber industries. The size of hardwood bark varies. It can be as small as a wood chip or as large as a nugget. The hardwood bark mulch is available in colors. These colors are added by using dyes on the hardwood chips. This type of mulch is popularly used around trees and plants that are perennial.
Softwood bark is also obtained from lumber and paper industries. One of the common softwood bark mulches is pine bark mulch. An important point that everyone needs to note about pine bark is the fact that it is slightly acidic in nature. It also takes very long to decompose when compared to other forms of organic mulch.
Bark mulches are wood based, they don’t mix well with the soil. Since wood mulches can be problematic to remove, they are used in places where you are not likely to do a lot of digging in.
Video | Choosing the Best Mulch
— Leaf Mulch
This mulch is generated from fallen leaves. It is the most economical and easiest mulch to generate since leaves are easy to obtain. People use leaf mulchers to make leaf mulch in fall. This mulch is easy to store and easy to use. Leaves which are not mulched can form a thick layer that can act as a soggy mat. In spring, this soggy mat of leaves can prevent the growth of new grass and plants.
Leaf mulch is popularly used in plant beds as it decomposes and mixes with the soil easily. The downside to this type of mulch is the fact that leaves can with infected with scab, leaf spot and/or anthracnose. Ensuring that the leaves are healthy is important or you may spread the diseases throughout your garden.
WORX WG430 | Mulch your Own Leaves
— Wood Mulch
This type of mulch is formed from the waste that is generated when trees are pruned. While pruning your tree in backyard doesn’t not necessarily generate enough lumber, people who trim trees in large areas of land certainly do. These branches of the pruned trees are very popular because a 3 inch thick layer helps to contain soil moisture content. It also helps regularize the soil temperature and keeps the weeds away.
Like the bark mulch, this wood based mulch does not mix well with the soil. Hence, it is used around trees and shrubs. It is important to note that there is a precaution of keeping a mulch free zone around soft stemmed plants is observed. This helps to prevent stem rot (due to excess moisture) and other diseases.
Video | Mulching Tips
— Wood Chip Mulch
Many people make the mistake of confusing wood mulch and wood chip mulch. The difference between the two lies in their source. Wood chip mulch is generated from processed and treated timber. This is usually obtained from packaging pellets.
— Cedar mulch
Another wood based mulch is obtained from Cedar trees. There is a difference in the types of Cedar mulch available. Some are obtained from Junipers which are also called Cedars. Other Cedar mulches are developed from the Eastern Red Cedar, the Western Red Cedar or the Southern Red Cedar. The first group of Cedar mulches has had a better outcome when compared to the second group. Research links this to the fact that Junipers grow on alkaline soil while the other Cedar trees require a more acidic kind of soil.
Unlike the other types of mulch, the Cedar has some interesting properties that can prove to be a boon as well as a bane. Freshly ground Cedar repels insects. It decomposes and adds weak organic acids to the alkaline soil. This helps the plants absorb the nutrients better.
The drawbacks on the other hand are linked to the fact that once the cedar oils evaporate, it leaves the raw Cedar wood with a high Carbon: Nitrogen ratio. This is the cause of the yellowing of leaves of plants that are planted in the vicinity.
— Pine Needle Mulch
This form of mulch is also popularly known as the Pine Straw mulch. It has gained popularity because of its renewable source. North California is one of the places that harvest Pine needle mulch every year. Another factor in its favor is that it is cheap. People even collect the pine needles when they fall and store them to be used as mulch later in the year.
— Cypress Mulch
Cypress trees are used to generate Cypress mulch. This mulch has a very fresh aroma and is known to act as an excellent barrier against weeds when it is 3 inches thick. Since it doesn’t breakdown easily, Cypress mulch is considered to be long lasting.
Unfortunately, Cypress has some significant disadvantages. Cypress trees mature over a 100 years. This means that to produce mulch a number of very old trees are being cut down. These trees have no way of being regenerated in the near future. This is why the environmental impact of using Cypress mulch is significant.
— Colored Mulch
Organic mulch has often been dyed red, brown or black. There are some other colors that are used but the most popular types of mulch are the ‘Red mulch’ and the ‘Black mulch’. Research has shown that the dyes that are used to color the mulch are not toxic. That is why colored mulches can be applied in all the places that non colored mulches are used.
— Aged Wood Compost
These types of mulch are derived from hardwood trimmings that have been kept to compost over time. To aid in the decomposition process, most of the hardwood pieces are chopped into fine chips or shreds. While this type of mulch gives an aesthetic look to the landscape, you will also find that it adds to the nutrient quality of the ground.
— Cocoa mulch
These types of mulch are made up of cocoa bean shells. The shells are a byproduct of the production of chocolate. Cocoa mulch has a number of desirable properties. It is light, easy to carry and smells like chocolate! Unfortunately the heavenly odor lasts only for a few days.
Cocoa mulch contains a naturally occurring stimulant called Theobromine. This stimulant is toxic to dogs and cats. So if you own a pet, it would be wise to stay away from the types of mulch that contain cocoa bean shells.
— Straw mulch
Straw has often been used as a protective layer in the garden. Since straw is light and can easily be blown away, a number of techniques are incorporated. These techniques can involve matting and crimping. Straw mulch is popular because it is cheap and has good water retention properties.
— Peat moss mulch
Also known as ‘Sphagnum peat’, peat moss mulch has gained itself a lot of popularity. This is because it is known to be long lasting and it comes in neat packaged parcels. When these types of mulch are wetted, they form a dense crust. This crust forms a barrier between the atmosphere and ground such that water cannot seep through.
It is also a very high source of carbon. Therefore it is not surprising that when it is dry, peat moss can be burnt.
Video | Best & Worst Mulch
Inorganic Mulch
Inorganic mulch refers to those types of mulch which are synthetic and are not biodegradable. While many people prefer the use of organic mulch, there are still a number of inorganic mulches that are popular.
— Plastic mulch
These types of mulch are composed of polyethylene. The polyethylene is a thin sheet or a layer which forms a layer above the soil. Since plastic is impenetrable, you will find that water, sunlight and nutrients cannot pass through it. This is why it acts as a great prophylaxis against weeds.
Plastic also helps retain heat. That is why it used to retain and maintain soil temperatures which can be vital for sprouting seedlings. Unfortunately plastic mulch does not do well in terms of long term use. This is because these types of mulch deteriorate when exposed to sunlight. Plastic mulch is meant to be used only for a single season.
— Fabric
There are different kinds of fabrics that are used. Some people use synthetic carpets, others just use the landscape fabric. Unlike the plastic mulch, the landscape fabric is meant for long periods of time. This means that these types of mulch can be used across different seasons.
The advantages of the fabric include the fact that it does not allow the growth of weeds. Since it is porous, it allows both water and air to circulate to the soil below. Landscape fabrics can be used on their own or they can be combined with organic mulches.
Electric Chipper/Shredder | Patriot CSV-2515
— Rubber mulch
Another popular inorganic mulch is Rubber mulch. It is made up of rubber generated from recycled tires. A lot of research has been done in this area and people are still studying how rubber mulches can affect our lives. The studies show that rubber can remain in the soil for indefinite amounts of time. They also indicate possible toxicity levels that can be found in the soil post use.
— Stone
The use of stone in landscaping is something almost every gardener/landscaper turns to. Stone also acts as a really good mulch. Some examples of stones that are used are crushed gravel, marble chips and even volcanic ash.
Stones don’t retain moisture and they retain a lot of heat which can cause damage to the roots. That is why these types of mulch work well at a good distance away from plants and trees.
Mulch Calculator | How Much Mulch Do You Need?
Research will tell you that an ideal layer of mulch needs to be 3-4 inches thick. While that does give you an idea of how much mulch should be layered on top of the ground, it does not tell you how much mulch you need to buy for a plot of land. Luckily for us, there is a formula that simplifies the whole process.
The cubic yards of mulch required = the specific area (square feet) of to be covered x depth (in inches) of the mulch required x 0.0031
Home Depot has an easy to use online Mulch and Top Soil Calculator. It’s the easiest way to calculate how much mulch you need.
Handheld Mulcher | WORX TriVac WG505
Mulch Installation Checklist
Before installing the mulch, you need to ensure that you have ticked the following things of your to do list.
- Soil drainage: Check to see if the soil drainage is sufficient.
- Plant species: Check to see if all the plants in the vicinity do well with the types of mulch you are using.
- Preexisting mulch: Check to see if there is any mulch that is already present. Check the depth of the mulch and break up the clumps of mulch.
- The stems and the tree trunks: The mulch should not be piled high next to the stems and the tree trunks. On the contrary, ensure that the mulch is pulled away so that the stems have space to breathe.
Mulch Installation In Landscape Beds & Planters
Installing different types of mulch in landscape beds and planters is a relatively easy job. All that you have to do is follow the step by step procedure given below.
- STEP 1: Mark of the area that you want to mulch.
- STEP 2: Clear all the undesired plants from the vicinity. How you do it does not matter as long as the weeds are removed.
- STEP 3: Use a weed barrier. A commercial weed cloth or even newspaper will do the trick. Apply this to the soil before putting the mulch. Solid plastic however is a definite no-no!
- STEP 4: Spread a layer of mulch that is 3-4 inches thick. Ensure that the layer is not more than 4 inches thick.
- STEP 5: Keep the mulch one to two inches away from the stem of the plants.
- STEP 6: Build an outer edge for the mulch to ensure that it stays in the location you have placed it. A small trench also works well. Other edgings are made up of wood, plastic, stone or even steel.
Installing Mulch Around Trees
Like the landscape beds and planters, the installation of different types of mulch around trees is a simple step by step procedure. Let’s take a look at how it is done.
- STEP 1: Make a circle around the tree that has a radius of 3 feet.
- STEP 2: Increase the mulch area by 1 foot for every inch of the trunk’s diameter. This rule holds true till 12 inches.
- STEP 3: Use a weed barrier just like how you did with the landscape beds and planters
- STEP 4: Apply a layer of mulch that is 3-4 inches deep. This is the gold standard for all types of mulch.
- STEP 5: Ensure that a gap is kept between the trunk of the tree and the mulch. The mulch should not pile up on the trunk.
- STEP 6: Organic mulch degrades after a period of time. Frequent top ups need to be done as and when required.
- STEP 7: Use an edging at the circumference of the mulch.
As you can see, there are many types of mulch that are available in the market. Some are easily available while others are not. Choosing a type of mulch for your setting requires knowledge about the plants in your garden as well as the mulch you are using. Cost also plays a very big role in making the choice.
Learn more about mulches and mulching:
- Mulches for Landscaping : Cornell University
- General Information on Mulch: Wikipedia
- Proper Mulching Techniques (PDF) : International Society of Arboriculture (ISA)
- Mulching Guide (PDF) : University of Hawaii at Manoa