To mulch, or not to mulch, that is the question. Fortunately for us, this question is easy. MULCH. Essentially, mulch is a layer of material applied to the surface of the soil. While mulch is usually some type of organic matter that will break down over time, it doesn’t have to be. Personally, I can’t see myself ever recommending something that won’t naturally break down over time to cover my soil…..but people have done stranger things….I try not to judge.
Adding mulch to your garden is probably one of the best things you can do for your garden. It is one of the best ways we can mimic the forest floor in our home garden. In this article I go through the top 7 reasons why applying mulch is important.
Table of Contents
Top 7 reasons you should use mulch in the garden
1. It adds organic matter to the soil
Organic matter is extremely important to soil health and improving soil structure. By using organic material to mulch your plants you are constantly feeding your soil. As the material breaks down, that organic matter is transferred into the soil. Ideally, your garden soil should be 10% organic matter (in a pristine forest the organic matter will be much higher than 10%, but it’s is a good goal for most home gardeners).
2. Reduced water loss from evaporation
Mulching helps reduce the amount of water leaving the soil’s surface through evaporation. The fine feeder root systems of most plants are highly susceptible to drought stress. If you have a busy schedule or just forget to water your plants consistently mulching can be a real lifesaver when it comes to keeping plants hydrated.
3. Helps maintain soil temperature
Feeder roots can be extremely sensitive to changes in soil temperature. Mulching does a good job of regulating soil temperature so that the soil stays cooler on hot days. Also, it helps keep roots covered, and protected. Roots becoming exposed are more likely to happen if you are planting in containers.
4. Protects the soil microbes
This point is a big deal that most people tend to gloss over. Microbes are extremely important to soil health. Keeping your soil microbial population healthy and in balance is going to eliminate at least 80% of your gardening problems. Mulching doesn’t just protect the physical soil it also provides a better environment for soil life such as worms, microbes and beneficial bacteria and mycorrhizal fungi which helps the overall health of the plant.


5. Suppresses weeds
“I just love weeds,” said no gardener ever. Weeding is the one time sucker that we all probably wish we could do less of. Staying on top of weed pressure is important. If you dislike weeds as much as the rest of us mulching is your new best friend. Utilizing mulch reduces the weeds access to sunlight. Without access to sunlight, the weeds can’t grow past their germination stage and will eventually die off.
6. Reduces soil loss
Bare soil is at the mercy of the elements. When soil is left exposed you will end up losing the upper layer of soil as the wind and rain blows over it. As weather patterns become more extreme due to climate change we have to do our part to protect our soil. Keeping the soil covered with mulch means less soil loss because of wind and heavy rains which means you get to keep more of the precious medium your plant needs to grow.
7. Reduce soil-borne diseases
If you’ve ever had a fungus problem in your garden it most likely came from your soil. Typically, soil-borne diseases get transferred to the plant when the soil, containing the fungus gets in contact with the leaves. This usually happens during periods of heavy rain or if someone watered the plants with too high a water pressure allowing the soil to splash on the leaves.
Using mulch on your soil creates a barrier between the soil and the foliage of the plants. This barrier stops the soil from splashing on the leaves of your plant. Thus, blocking Foliage fungal disease spores from getting to your plant.
What should I use to mulch my plants?
When picking a material to use to mulch I would first look for something that breaks down at an acceptable rate over time. If you choose something that breaks down relatively quickly, like grass or leaves, you will end up needing to add new material more often. Also, It has to be heavy enough that it isn’t going to get easily displaced by rain or wind. And lastly, you will need to be able to source it in bulk and get it either extremely cheaply or for free.
What you don’t want to use is something that is going to increase weed pressure, or pollute your garden with pesticides, plastics or any other unwanted material.
In order from my most favourite to the least favourite option, some of the materials that you can use to mulch are:
- Pine needles – Pine needles are relatively easy to find. If you are in North America you should be able to find some pine trees in your area. If you are in Trinidad pine trees are around as well, you may just have to look a bit harder. The plus side is, once you’ve found a tree you probably will have more than you need for years to come.


2. Straw – If you’re in a rural part of the United States this is probably going to be relatively easy to find for maybe $2 to $3 a bail or even free. If it isn’t accessible to you you can also consider just ordering online.
3. Shredded leaves and trees – If you’re lucky enough to have some mature trees in your garden or know someone that does landscaping this is a great way to get free mulching material. The safest option would be to use material from your yard. That way you are sure you aren’t introducing a pest or disease problem into your space. Additionally, consider sending the material through a shredding process before using it around your plants. This increases the surface area so the material will break down faster while the irregular pattern after shedding will allow for good airflow while still adequately cover your soil.
4. Woodchips – These can make a really good mulch. They don’t break down as quickly as leaves or grass clippings so you won’t have to reapply as often. However, not all woodchips are created equal. A hardwood variety is always preferred over a softer wood variety. Softwoods tend to take nitrogen from the soil when they break down while some hardwoods, like immortelle, can actually add nitrogen to the soil. Also, I generally avoid coloured wood chips as I generally try to avoid adding anything unnatural to my garden if I can. If you decide to use woodchips try to get as much information as you can about what type of wood it is and where it came from. There are a few trees that will actually leach toxins into the soil as it breaks down. The more information you have the better off you will be.
5. Grass clippings – Grass clippings are usually easy to find. They are free, and available almost everywhere. Personally, I find grass clippings as a mulch in the garden problematic. Grass clippings tend to compress as it breaks down. This compression will lead to a reduction in the airflow which can cause the process to go anaerobic. Also, if the grass has weed seeds in it these seeds can germinate in your garden and cause huge problems with weed pressure. If you ultimately decide grass clippings are the way to go for you, don’t pile them on too thick. Green materials like grass contain a lot of moisture. As that starts to break down it is going to heat up. If it’s piled too high it will raise the soil temperature and could potentially kill your plants.


6. Rubber mulch – Rubber mulch is essentially made of rubber tyres. While they do work in some of the ways I highlighted previously I would NEVER use this in my garden. These things don’t add to build quality soil and who knows what chemicals you may be leaching into your soil.
When not to mulch
As great as mulching is there are a couple of scenarios where I would not mulch. The first applies to people growing outside of the Caribbean. If you are in a colder climate and trying to grow garlic or some lettuce varieties in late spring or early summer I wouldn’t mulch these. Because these plants require a lower soil temperature. Mulching in this case could cause the temperature to be too high and the plant won’t develop as it should.
The second scenario is if I have planted my seeds directly into the soil (i.e. direct seeding instead of transplanting). In the same way, mulch is great at smothering weeds and keeping the weed pressure down, it can also smother your plants that are just germinating. In this scenario, I would keep the area clear until the plants are well established and only add mulch once they are a bit more mature.
Dos and Don’ts when adding mulch to your soil
Do:
- Consider free resources in your area you can collect these materials from.
- Shred your leaves, or any other material you decide to use if you want it to break down faster.
Don’t:
- Till your mulch into your soil as some materials can rob nitrogen from the soil
- Be mindful as some leaves (e.g. black walnut) can be toxic when it begins to break down
Final Thoughts
Protecting your soil is one of the most important things you can do. One of the easiest ways to do this is to keep your soil covered with an appropriate organic mulch. Using an organic mulch in your garden will increase the levels of organic matter in the soil as it breaks down. This increase in organic matter will improve soil structure, water-holding capacity, nutrient mineralization, biological activity, and water and air infiltration rates.
Mulching will create a layer of organic matter on top of your soil. Worms will naturally transfer this layer down into your soil. This layer of organic matter will also naturally penetrate the soil over time. Soil microbial activity and organic matter are the two most important things you can manage in your garden. And, one of the best ways to do that is to keep your soil covered with an appropriate cover of organic matter.
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