Compost vs. Mulch: What’s the Difference?


If you find yourself asking compost vs mulch, you’ve come to the right place. If you have taken up the hobby of gardening, you must familiarize yourself with different types of soil and the things that will give your soil what it needs. Both compost and mulch are good for your soil, but they help it in different ways.

So, are compost and mulch the same thing? Compost and mulch have some similarities, but they provide different benefits to your gardens.

Basic differences between compost and mulch include:

Compost Mulch
Made only of decomposed organic matter Can be either organic or inorganic
Feeds soils Protects your plants
Promotes growth Helps to prevent weed growth

In this article, you will get an in-depth look at the similarities and differences of compost and mulch and how they can both benefit your garden.

Differences Between Compost and Mulch

Compost is made from decomposed organic matter. It’s made up of things like grass, old fruits and vegetables, and newspaper scraps. Its ratio is usually 2 parts “brown,” or things that aren’t food, and two parts “green,” which can be vegetables and grass. You can also use eggshells, fruit skins, old paper towels and other “brown” materials for your compost.

Compost is put into your soil and can be plotted into the same hole you are going to put your plant in. If your plants are already in the soil that is fine; you can just mix the compost into the soil with a fork. The main purpose of using it is to give your plants nutrients directly at their roots.

Compost is a product that conditions the soil instead of simply being a fertilizer. With compost, the concern comes from making sure there isn’t too much salt or manure in it because you can either give your plants burns or encourage weed growth. It’s important to note that just using manure alone is not the same thing as compost and is not recommended for food gardens.

Mulch, however, is the organic material that is put right on top of your soil to shield it from harsh outside forces. It also keeps all your moisture in and helps the soil stay nice and warm. Mulch will decrease the amount of erosion as well and gives nutrients as it breaks down slowly.

You can put grass, straw or leaves in your mulch. It doesn’t have to be the mulch you think of when you visit a children’s playground. You can use that if you’d like, but there are ways to make a more organic mulch that will deliver the vitamins and minerals that your plants need more quickly.

Some less organic versions of mulch are rocks, gravel, and plastic. You can also use wood chips, which will decompose to some degree. Mulch is your weed barrier and is the last thing you put over your soil and compost.

Organic mulch will be made up of larger particles, which means that, although it is organic and will decompose, it takes much longer for it to break down compared to your compost.

Be careful not to use something called green waste in your mulch. Green waste is a wooden mulch that has been made of trees that need to be composted. Mulch and compost are different, and you can’t use one as the other, even if they do have some similarities.

Similarities in Compost and Mulch

  • Nutrients

One similarity is that both will eventually give the soil nutrients. Compost delivers nutrients almost immediately, but mulch delivers them over time.

Mulch can be made up of things like grass clippings, hay, leaves, and other organic leftovers. This means, like compost, it will break down over time providing benefits to your plants through the soil. As the nutrients in compost vs mulch, it will help your plant grow faster, speeding up harvest times.

  • Do It Yourself

You can make your own compost and mulch, but they also sell premade packages of each, Premade compost will have the proper ratio of brown and green items talked about earlier. Usually, the mulch you will find most often on the market is wood chunks.

It helps to shred up things like newspapers for your compost, and if you want to, you can also shred up your veggies. You can use a garbage bin for your compost or make your own with things like milk crates, wire, or boxes. You do have to make sure to store it in its own separate section where good bacteria and things like fungi can grow and enrich the compost.

You can make your own mulch in the same way, but instead of adding items that are used in compost, you add items used for mulch. This should also be stored by itself.

  • Conservation

With both compost and mulch, you want to make sure not to use too much. There is such a thing as too much mulch or compost. If you dig a hole for your plant and fill the entire hole with compost, you are overdoing it.  

Your plants need a certain level of air, sunlight, and moisture. Putting too much compost or mulch does more harm than good for your plants.

  • Less is More

If your soil is overloaded with too many rich nutrients, then there will be an excess number of things like phosphorus and potassium. The plants will not be able to handle it and ultimately will end up dying. This is where the phrase “less is more,” will come in handy.

Too much mulch can increase the damage done by voles and smother plants in seasons in the winter especially, which encourages rot.

  • Growth

You need both compost and mulch to increase the growth of your plants. The compost does this directly while the mulch takes more of a protecting route, but they both ultimately will do your plants good and provide them with the nutrients they need to thrive.

  • Soil health

Besides the plant’s health, these two work together for the health of the soil as well. Things like earthworms will come and eat the compost protected by your mulch, and as they eat, they loosen up the soil. This will keep your soil from being too compact and will allow plants to very easily dig deeper into it.

When to Use Compost?

Working in a garden is a fairly simple task that beginners can do with little difficulty when getting started. Keeping some plants alive is difficult, and beginners will have to use trial and error to learn, adjusting their technique as they go.

First, you need to establish where exactly compost goes into the planting process. There are two different ways you will deal with compost.

You will either use compost in your soil for your plants, or you will make a soil and compost mixture that you can use as needed. Using compost in your plants will give them everything they need to grow properly. Making a soil and compost mixture is done by introducing both compost and worms to your soil in a separate pot to condition it for later use.

In the first scenario, you are going to use compost directly in the soil that you will put your plants in.

  • Mix your parts of green and brown and combine them with your soil, making sure that you have an equal distribution of compost to the soil.
  • Dig a hole for your plant and pour 1/3 of that hole with compost before using the rest to plant either the roots or the seed, covering it back up with soil.
  • You can also pour the compost directly over the top of your soil. It will seep into the ground on its own creating a conditioning treatment for the top bed. Even if you don’t plant the compost into the ground, the benefits of it are still there when you layout new plants. You only need to change your compost once a year.

In the second scenario, you will be creating a compost and soil mixture:

  • The other time that you want to use compost is to make a pot with just the soil and compost and introduce some red worms into it. They help fertilize the soil and make your compost mix even stronger so that when you go to use it the “ingredients” in them are already active.
  • This should be done in a separate pot from the plants since the worms would eat the plants. You just scoop it out as needed.

How often you change or introduce new compost depends on how frequently you introduce new plants. If there are no new seeds in the ground you can follow the previous advice of only applying new compost once a year.

When to Use Mulch?

Mulch is often used for decoration. However, it is used in gardening in a very similar way to compost with different benefits.

When using mulch, you want to follow these steps:

  • Plants your seeds.
  • Place your compost.
  • Scoop your mulch onto the surface of your soil, making sure that it is being placed evenly.
  • Do not mix the mulch into the soil. It must be on top of it to create a barrier between the growing plants and outside forces.

Mulch also prevents weeds from growing, so if you are having a weed problem, it would be an excellent time to try out mulch. Use about three inches of mulch when spreading it over a bed of soil. There is a fine line between too much and too little mulch, and you don’t want to impair its ability to conserve moisture or fight weeds.

You should change your mulch out twice a year. Usually, you change it out around the spring and fall seasons. Some people change their mulch out once a year like they do compost. When removing the mulch, you want to be sure to till your soil and add your new compost.

You can use organic mulch to help increase the fertility of your soil since the mulch will decompose as well as the compost, though the mulch will do so at a much slower rate. You could also use mulch for its aesthetic value because some companies offer mulch in various bright colors to go with any exterior decorations, paint, or plants you want it to match.

Since mulch is inexpensive, you can use it at any time. Beginners should be sure to cover their gardens with mulch to shield their plants and give them a better chance of surviving and thriving. Mulch is so easy to use that it can be utilized at any level of gardening skill and needs little instruction or maintenance.

How to Mix Your Compost with Soil

Compost should be properly mixed into your soil in order to maximize its benefits. This can be accomplished in four easy steps.

To mix compost with soil, follow these steps:

  • Measure

First, measure out how much compost you want for your soil. This can be accomplished by a simple rule of adding about 40% compost to your soil blend and 30% compost to your soil bed. When mixing compost with your soil, make sure that the consistency is not too wet or too dry.

If it is so dry that it is crumbly or more than damp, then you haven’t got the right consistency. Pour out your compost mix into a gallon pot. After you do this, take some saran wrap or a plastic bag and put it over the top of the pot, making sure it’s sealed up.

  • Placement

Next, take your sealed compost pot and move it so that it is placed in a spot with sunlight. This will disinfect the soil. The sunlight will also kill any weeds that might grow and steal the nutrients from the seeds. Let this sit out for about two weeks or longer.

The sun will dry it out, though, so if you want to hasten the process of getting your compost mixture ready, you can spray it occasionally with water. Don’t get it waterlogged but spray enough water that it can retain a level of moisture similar to a dampened sponge.

  • Soil Blending

After you wait the appropriate amount of time, go ahead and take the pot of compost back to your garden. Get yourself another pot with no holes in the bottom or a bucket and move one scoop of compost to the new bucket. Then, add two scoops of soil. (You can add the soil first if you’d like.).

Taking a shovel or other sturdy stirring tool, mix the two together until the compost and the soil look thoroughly blended. You can tell that it’s been mixed enough once the compost blends in with the soil.

  • Dumping

Once done, dump out your mixture into another bucket. This bucket should be around five gallons. You repeat step three in your empty bucket until the third bucket is filled with enough composted soil. You don’t need to mix this third bucket, but you can if you want to.

After you do all of this your compost will be thoroughly mixed in with your soil and ready to be used in any sort of plant bed you want.

Are Compost and Mulch Necessary?

So, you now know how to mix your compost together, what compost and mulch are made of, and the benefits of both compost and mulch. But the question that may still be on your mind is this: Are compost and mulch really necessary?

In the technical sense, no, compost and mulch are optional components to your gardening bed. They aren’t a necessary component of planting; however, there are so many nutrients in them (compost especially) that they improve both the plants and the soil.

So, while they are not required, compost and mulch are two things that you want to consider if you take planting seriously. If your plants are struggling with weeds, mulch can be a necessary step to take to fix this issue. If you are struggling to get your plants to grow, you might consider things like a compost bin of your own or store-bought, or fertilizer.

Is Compost Fertilizer?

No, compost is not fertilizer. The main difference between compost and fertilizer is that fertilizer is made to just feed your plant. Your compost is made mainly for the soil which stimulates the plant. So, even though you use fertilizer, your plants will still benefit from compost.

Final Thoughts

If you are asked if compost and mulch are the same things, you should be able to confidently say, “No, my compost enriches the soil and plants, and my mulch organically shields the plants.” This knowledge will make you a much more successful gardener.

Compost, mulch and even fertilizer are very similar; therefore, most people don’t know the difference because they all are beneficial to your plant ways that may be mistaken as interchangeable. If you are serious about your gardening, you should know how they are similar and different and how to use them to make your garden thrive.

Eyerly Family

The Eyerly Family is a family of 8 that loves gardening. Over the past several years we have been applying what we learn about gardening to our own 16x16 raised back yard garden. Our garden is very prolific and we grow a wide variety of vegetables which we love to eat! Click here to learn more about the Eyerly Family.

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