Humus Vs. Compost: Definition, Benefits, And Other Gardening Tips

Many gardeners who are not too concerned with technical terminologies often use these two words interchangeably. If you are one of them, perhaps you have been wrong this whole time.

However, it is not too late to learn the difference between humus and compost. This article will help you distinguish between these two soil ingredients, for what purpose they are used, and how you can make one or both of them.

What Is Humus?

Humus is the black substance that remains when dead plants and animals fully decay. Therefore, it is spongy and amorphous.

The process that the humus is formed is called “humification.” During humification, microorganisms decompose organic materials and turn them into inorganic minerals and humus.

Minerals, like nitrogen, potassium, and magnesium, come back to the plants as essential nutrients. Humus, the stable matter that can no longer be broken down, is now part of the soil structure.

Humus Vs. Compost: Definition, Benefits, And Other Gardening Tips
“humus” by po.psi.que is licensed under CC BY-SA 2.0

Humification often happens in nature: fallen leaves, dead animals, and mushrooms on the forest floor, in the swamps and bogs. This process takes a long time to reach the final product that is humus.

There is garden humus too. We will explain how it is created in the next section.

What Is Compost?

Compost is the mixture of decomposing plants and food waste. Most of us are more familiar with compost since we all have a compost bin next to our trash and recycle bins at home.

During the composting process, organic materials are broken down into beneficial organisms and nutrients for plants.

If that sounds familiar to you, it is the same process for humus that we just mentioned. The difference here is that humus has already reached a stable state.

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On the other hand, compost is formed when microorganisms are still diligently working on decomposing the organic materials.

Compost Vs. Humus

Essentially, compost and humus are different states of the same process. Compost is when the organic materials are still being decomposed, and humus is when the decomposition is “finished,” resulting in organic matter.

From the definition, it is understandable why humus soil is rarer to find in a garden setting.

In nature, organic materials have a higher chance of being undisturbed for an extended period. Thus, the tiny creatures in the soil have the opportunity to break down more and more molecular particles until nothing can be broken down anymore.

Since hummus is fully decayed compost, it is richer in nutrients. And the quickest way to boost humus in a soil is to add more compost.

These two soil components go hand in hand, so it is understandable why they are often caught in the humus vs. compost debate.

Here is the summary of the difference between compost and humus:


  • Fully decayed organic matter
  • Stable condition
  • Product of composting
  • Black, spongy, amorphous


  • Decomposing organic materials (plants, food waste, animal manure, etc.)
  • Unstable condition
  • Containing humus
  • Remains of organic materials can still be detected

Compost vs. Humus: What’s the Difference?

What Are The Use Of Compost and Humus?

Humus and compost significantly improve soil condition. Here is how these organic parts of the soil work:

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PH Balance

Soil can get too acidic or too alkaline for your plants sometimes. Therefore you might need to add sulfur in the former and lime in the latter situation to balance out the alkalinity of soils. Humus would buffer the soil and help it maintain the desired pH level.

Oxygen And Nutrients Retention

Humus and compost enhance soil porosity. This enhancement helps the roots to penetrate deeper while providing breathing air for the beneficial microorganisms.

Water Retention

Two common problems concerning the density of soil are sandy soil and clay soil.

Sandy soil is formed of large particles with lots of air space, resulting in low water-holding capacity. Adding the organic layer to this soil would help the large particles stick together to ensure moisture retention.

Clay soil, on the contrary, is compacted soil, holding too much water, rotting the plants. Humus and compost would turn them into larger clumps; therefore, water can be drained.

Pest And Disease Control

Humus and compost contain active microorganisms that process nutrients for beneficial micro-organisms. These macro-organisms, in turn, feed on the larvae and eggs of destructive pests and insects.

Composting Basics

Now that you know the importance of composting, here is the guide to be an intelligent gardener:

Two Types Of Organic Materials

Greens and browns composts are two main types of organic materials. Ensure you categorize the waste and stick to the 3 browns:7 greens ratio for best compost mixtures for plants.

Too much of any substance will make your plants produce fewer fruits and flowers, or even worse, can kill them.

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Two Ways To Compost

Anaerobic decomposition happens in the absence of oxygen and will result in gases like methane. This is a longer process. Doing it at home would require more work. Therefore this method is less popular.

Aerobic decomposition happens in the presence of oxygen. This process usually does not produce any questionable odor and is the preferred option for most households.

Tips To Speed Up Decomposition Rate

  • Turning the pile regularly: This action shortens the decomposing process 3 to 4 times. Make sure you wear gloves and a mask while doing this.
  • Provide enough moisture: The lack of water prevents the growth of the microorganisms that break down the organic materials. Too much water, on the other hand, creates undesirable anaerobic conditions.
  • Grind and chop organic materials into smaller particles: The microbes would take less time to consume these small pieces.
  • Wait until the original ingredients are unidentifiable to use: Unfinished compost can hurt the plants.


By now, you have the answer to the question humus vs. compost: what is the difference? They are not the same thing but slightly different states of the same thing.

It is also essential that you understand the advantages of compost. Apply the tips mentioned in this article to achieve humus-rich soil. Enjoy your time outdoors contributing to the planet earth!

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Jill Sandy

I am a sustainable focus gardener. I love decorating my home backyard with beautiful landscape design and creative garden care techniques I develop myself.