Different Types of Mulch

Different Types of Mulch: Which is The Best?

Mulch may not be a miracle solution to all your garden troubles, but according to many professional gardeners, it certainly comes close!

With that in mind, it’s good to note that different materials fall under the title of mulch, all serving a single purpose – improving the soil condition. 

Mulching preserves soil moisture, keeps soil temperature stable, prevents soil compaction, keeps weeds away, prevents soil erosion, and protects delicate plants. As if that is not enough, mulching makes your planting beds attractive.

Hereunder, we’ll look at the different types of mulch to help you choose which best suits your needs.

Types of Mulches

Mulches can be categorized into two classes, namely organic and inorganic mulches. Let’s see these two classes in detail and the different mulches falling under each.

Organic mulch

Organic mulches are your part-time fertilizers. With time, these mulches will decompose into your soil, providing nutrients that will boost the growth of your plants.

Since organic mulches decompose over time, you will need to reapply them almost monthly.

One more great thing about organic mulches is that they are environmentally-friendly. 

That said, here are the most common organic mulches:

Straw mulch

Straw refers to the dried-up stalks of grain plants, e.g., wheat, rice or oat. This mulch is light in weight, meaning you don’t need a lot of effort applying it in your garden.

However, straw mulch decomposes quickly; therefore, you will need to reapply it after a month on two.

Straw mulch

Wood chips

Regular or dyed wood chips are made from tree trunks and branches. Also, most unsold Christmas trees end up here to make some colored mulch.

Some wood chips retailers sell for mulching are often treated to prevent weeds from spreading, promote color longevity, and reduce flammability. Also, the dyes used on these mulches are safe for the environment. 

Due to their large sizes, you can best use wood chips in places least disturbed.

However, one downside with wood chips is that water can easily wash them away; you may find yourself oftenly picking and returning to place migrated wood chips. Therefore, ensure you don’t use this mulch in hilly places.

Wood chips

Arborist’s wood chips

This wild mulch often contains many leafy materials and other parts from trees, shrubs, and other woody plants. This combination is helpful since it keeps the mulch from compacting. 

Arborist’s mulch is inexpensive, and sometimes you can get it free if you know who to call. You can even stop a truck and ask it to dump the wood chips in your garden for free; after all, they’d have paid a fee at the dumping site.

This mulch is safe to use even if it is not processed or treated since insects and bacteria die as the wood chips dry out. But you can follow up on the trees treated with insecticides and get mulch from these if possible.

Remember, not all arborist’s wood chips are safe to use in the garden; avoid wood chips from walnut trees, eucalyptus, and trees from heaven. 

Another amazing advantage of this organic mulch is that it decomposes slowly, making it perfect for landscapes and saving you from frequent mulching. Also, this mulch absorbs moisture, thus keeping your soil damp. 

Arborist_s wood chips

Shredded bark mulch

Shredded bark mulch is light in weight, consisting of smaller chips but not easily carried away by rainwater.

This mulch is made from different trees and shredded into fairly uniform pieces. Also, this is one of the cheapest mulches in the mulching market. 

Shredded bark mulch decomposes slowly, meaning it will serve your landscape longer.  

However, this mulch can absorb nitrogen from the soil when decomposing. Therefore, ensure you supplement this mulch with some fertilizer when using it with nitrogen-loving plants.

Additionally, other shredded bark mulches have some bonus benefits. For example, aromatic cedar can help eliminate insects from your garden.

Shredded bark mulch

Grass clippings

Grass clippings are the easiest to get; just collect them after mowing your lawn. And they are easy to use too!

This mulch is an excellent source of nitrogen for your plants and has a fine texture that won’t harass your vegetables. 

But, there is a downside – the smell of decomposing grass! Yes, we all know freshly cut grass smells great, but the nice smell won’t stay long; the grass will begin to release a bad odor when decomposing.

The odor can stay for a week or two. So, it will be best to use grass mulch in places far away from the house. 

Grass clippings

Leaf mulch

There is often a generous supply of leaves during autumn. So, if your lawn mower has a bag, run them over, then empty the chopped leaves into your garden. 

A thick leaf mulch will insulate your ground during winter, thus making the roots of your plants happy. 

But, keep away from the temptation of just raking your lawn and dumping the whole leaves in the garden. If you skip shredding the leaves, then it will be more likely that they will compact and grow mold. 

Also, using unshredded leaves means no aeration, and moisture may not find its way to the soil.

Leaf mulch

Pine straw mulch

Pine straw is simply dried-up pine needles. Like other mulches, such as grass clippings and leaf mulch, pine straw is readily available if you’ve got the right trees.

All you do is just sweep, collect the needles and apply them to your landscape. Also, you can buy pine needles in bulk and at a lower price than bark mulch.

Pine straw mulch is great at insulating the ground, filtering water and preventing soil erosion. Also, this mulch is perfect for plants that love growing in acidic soil

Pine straw mulch

Newspaper mulch

Where do you take your old newspapers? Out with other trash? 

Newspapers can form a good mulch; just shred them and apply them to your ground. Again, remember not to be tempted to lay the newspapers when whole on the ground; shredding them helps with aeration.

“Newspaper mulching suppresses weeds but allows moisture to reach the soil” – Paul F, Gardening Enthusiast.

For a solid newspaper mulch, you will need to shred quite a number of newspapers. So, if you don’t have enough old newspapers, you can get some more from your neighbors, friends, local newspaper shops, schools, and even libraries.

However, newspapers can become matted, forming a thick layer. Therefore, you’ll need to break up the mulch occasionally.

Newspaper mulch

Cardboard mulch

There are two different ways in which you can use cardboard in mulching: 

First option: place the cardboard in areas where you want to suppress weeds. Ensure you soak the cardboard in water and pin them down to prevent them from being carried away by the wind.

Well, this is not an attractive mulch, and many people will apply another type of mulch on the cardboard to make the landscape mulch more appealing.

Second option: shred up the cardboard before applying it to your ground; this allows aeration. Additionally, plastic-coated cardboard won’t decompose quickly, meaning you won’t have to mulch often.

For the pizza boxes, you can only use them if they have minimal or no grease stains.

Cardboard mulch

Compost mulch

You can make compost at home or buy some from local mulching masters. The best thing about using compost is that it will add nutrients to your soil besides serving as mulch.

However, since there are different types of compost, you will need to go for the one that bests suits the needs of your plants. For example, coffee grounds compost has mild nitrogen while mushroom compost has relatively low nutritional content.

One more thing to note with compost mulch is that it decomposes very quickly; thus, you will need to reapply it often.

Compost mulch

Cocoa shells

This mulch is brownish and light in weight. Additionally, cocoa shells add some nutritional value to the soil for healthier plant growth. 

However, if you are super sensitive to smell, you can judge if the odor on cocoa shells is a take or a throw.

Lastly, this mulch contains potash which can be harmful to some plants. Therefore you shouldn’t apply this mulch beyond a depth of 2 inches.

Cocoa shells

Inorganic mulch

Unlike organic mulch, inorganic mulch will not inject your soil with fertilizer doses. 

But the best thing with inorganic mulch is that it is long-lasting; you can change it yearly. So if you want a low-maintenance mulch, this will be a great choice.

Let’s now look at the different inorganic mulches you can choose from.

 

Pea gravel

This mulch is good at preserving soil moisture and suppressing weed growth. Another advantage of this mulch is that it doesn’t decompose, thus serving your ground for a long period.

Pea gravel may not be perfect for yards where you will need to attend to soil often. However, you can use this mulch for decorating landscapes. For example, you can add it under trees or shrubs.

Pea gravel

Rubber mulch

Rubber mulches are made from shredded rubber products, e.g., recycled tires. Additionally, you can hardly tell this mulch is made from rubber since it resembles many other mulches.

Like other inorganic mulches, rubber mulch is long-lasting, stays in place, and is bacteria-free. 

The best places to use rubber mulch are on landscapes and not in your vegetable garden. Also, since this mulch doesn’t decompose, it won’t add nutrients to the soil.

Lastly, you will need to remember that rubber mulch is flammable. So, ensure you use it away from fireplaces. 

Rubber mulch

Pumice rock

We have seen tire byproducts, arborist’s byproducts and even pizza byproducts, and now we’ll see volcano byproducts. Pumice rock results from volcanic eruptions. And you can use it to mulch.

Pumice rock features large sizes, which helps with ground aeration and prevents soil erosion. 

This rock can absorb water, making it perfect for water-logged soils. Also, you can use this mulch with desert plants since they don’t like a lot of water.

Even though pumice rock absorbs moisture, it still qualifies to be termed as inorganic matter since it doesn’t decompose nor release nutrients to the soil. 

However, with time, this rock will break into smaller pieces making it less useful and thus requiring reapplication.

Pumice rock

Plastic mulch

If you are looking for a pretty inorganic mulch, plastic mulch doesn’t fit that category. However, this mulch is very efficient in vegetable gardens. 

But how do you use this mulch? Just arrange your plastic sheets on the soil and cut holes to allow your plants to sprout.

One of the main benefits of plastic mulching is that it can cover wide spaces efficiently. Also, this mulch preserves soil moisture and prevents weeds from coming up.

Like other inorganic mulches, plastic mulch adds no nutrients to the soil. 

Additionally, you will need to have a compatible watering system in place. Watering from the top will leave the sheets flooded with no water reaching the soil. So, it will be best to have drip lines at the base of your plants.

Plastic mulch

Concerns in Mulching and their Solutions

Table 1: Using mulches to manage landscapes – concerns & solutions

Concern

Solution

Spreading plant diseases

● Use compost mulches
● Keep mulch away from trunks

Rodent damaging your mulch

● Avoid straw mulch
● Keep mulch away from trunks

Sour mulch

● Turn mulch until the sour smell disappears
● Store mulch in a well-drained place
● Avoid storing your mulch in huge piles

Nuisance fungi

● Use composted mulches
● Water mulch after application 
● Use rock mulch in places near vehicles or buildings

Termites

● Ensure your mulch is not near window sills, foundations, and siding

Slime molds

● Rake mulch to break the fungus
● Use composted mulches

Soil nitrogen depletion

● Use composted mulches
● Do not dig mulch into the soil
● Avoid mulches with carbon-to-nitrogen ratios (C:N)

Allergic to mulch

● Wear masks or protective garments when handling mulch

Excess moisture at the base of trunks

● Apply mulch 6 to 12 inches away around the trunks

Soil oxygen depletion

● Limit the depth of mulch
● Use coarse-textured mulch

Source: IOWA Department of Natural Resources

Conclusion

We have seen the different types of mulch, organic and inorganic. The main roles of these mulches are soil moisture retention and weed control. 

However, if you’d love some mulch that adds nutritional benefits to plants, organic mulch will be the way to go. But if all you want is a beautification mulch for landscapes, you can’t go wrong with inorganic mulches.

In need of more gardening tips or even socializing with fellow gardeners? Please check out my next article on that: Top 30 Gardening Forums, Communities, Discussion, and Message Boards

Resources

  1. Different Mulching Materials and How they Affect Soil Moisture and Plant growth
  2. Efficient Organic Mulch Thickness
  3. What mulching does to Soil Properties
  4. Mulch Vs. No Mulch
  5. Effects of Three Different Mulches on Zinia Growth, Soil Characteristics, and Weed Control
  6. Sustainable Landscapes using Mulches
  7. Effects of Organic Mulch on Weed Species
  8. Effects of Different Mulches on Growth and Yields of Different Vegetables
  9. Why Mulching is Important in Dry Agricultural Areas
  10. Organic Mulching – A Water Saving Technique
Robert Silver

Robert Silver

Robert Silver is a writer, speaker and certified master gardener who has been sharing his landscaping experiences through personal blogs. Taking it to the next level, Robert Silver has come up with this progardeningblog.com to shine a light on new planters and experts, discussing plants, landscape projects and much more. He has published numerous research articles on horticulture that have helped many people attain fruitful outcomes.