Mulch and compost are not synonymous. Simply put, mulch is applied to the top layer of soil to help control weeds, retain moisture, and regulate temperature, whereas compost is applied beneath the top layer of soil to benefit the soil by providing essential nutrients.
What is Compost?

Composting is an aerobic process that converts organic ingredients into nutrient-rich soil amendments through natural decomposition. Composting accelerates the decomposition process by creating an ideal environment for bacteria, fungi, and other decomposing organisms to do what they do, which in this case is act as a catalyst. Compost, or organic matter, is the end result of decomposition and is dark brown with an earthy scent. Humus is essential for soil fertility.
Pros of Composting
- Composting at home takes away from at least some of the waste that would otherwise go to landfills. It is extremely expensive to keep up with waste management in the United States, so if we can reduce that, it would be beneficial for everyone.
- If we could get everyone to use a zero-waste strategy through composting and recycling, we could stop much of the waste from being produced in the first place. This would mean tons of carbon emissions would be prevented.
- Compost contains the NPK nutrients required by garden crops. Instead of using these nutrients in fertilizers, we could use compost to improve soil water retention, productivity, and resilience.
- Due to the fact that soil containing humus increases water-retaining capability, farmers would not have to use as much water, saving water in the long run.
Cons of Composting
- The pros of composting definitely outweigh the cons on a grander scale, but many of the cons include things that would affect you immediately, such as the unpleasant smell, the initial investment, and the work involved. Composting is not for the lazy. If you want to start composting, you must be diligent.
What is Mulch?

Mulch is any material used to cover the soil’s surface. While all compost is made up of organic material by definition, not all mulch is. Wood chips or shavings, hardwood, and softwood bark are the most common types of mulch sold in bulk or bags at garden centers. Mulch can be made of many things, and there are also mulches that do not decompose and end up contaminating the environment, so always try to choose organic.
Pros
- Mulch is very beneficial as it can assist in suppressing weed growth, retaining moisture, and reducing sun heat damage by blocking sunlight.
- Mulch (especially straw or hay) can also reduce soil erosion by protecting the soil from the elements.
- Organic mulches can decompose and provide nutrients to the soil while also encouraging beneficial soil organisms and worm activity.
- Mulch can also be used to prevent some crops from rotting by lifting them off the ground.
- Mulch can save you time, money, and water because it slows evaporation meaning that you don’t have to water as often.
Cons
- Mulch is great for blocking sunlight, but this can be bad if you are trying to germinate seeds. To combat this, ensure your plants have greened up before mulching.
- Because mulch retains moisture, there is a possibility for the area to turn into a wet, muddy mess if there happens to be heavy rain. If this happens, remove the mulch, and allow the soil to dry before placing it back.
When to Use Which?
Your goal will determine whether you use compost or mulch. Both are beneficial for different reasons, but ideally, you should compost and mulch your garden beds with as much of your yard waste and kitchen scraps as possible.
Compost
If your primary goal is to enrich the soil by adding nutrients and improving its texture, work mature compost into the into the top few inches of your garden soil. Compost is usually used when it has broken down to a consistency the same as soil. It improves a soil’s structure and increases the availability of existing nutrients. Compost can be used to amend a given soil by mixing it in with the existing soil or by spreading it on top and allowing it to leach down through the soil profile over time.
Mulch
If your main concern is to keep the weeds down and cut down on irrigation, apply mulch, preferably one that decomposes over time, so you get the added benefit of improving your soil.
Mulch is used to suppress weed growth, moderate soil temperature, conserve water, prevent soil erosion, and can decompose over time (eventually becoming compost) if made of organic material. Mulch is applied on top of the soil as opposed to being mixed in.
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