Learn why charcoal is important in a terrarium! Discover its filtration and soil improvement benefits, ability to prevent harmful growth and control odors, types of charcoal to use, and alternative methods. Find out how to maximize the benefits of charcoal in your DIY terrarium project!


Terrariums have become popular among plant enthusiasts, as they offer a unique and captivating way to display plants and create miniature ecosystems. When it comes to DIY projects involving terrariums, one important element to consider is the use of charcoal. But why is charcoal important in a terrarium? In this article, we will explore the benefits of using charcoal in terrariums and how it can contribute to the overall health and success of your DIY project.

Charcoal for Filtration and Soil Improvement

One of the main reasons why charcoal is important in a terrarium is its powerful filtration properties. Charcoal acts as a natural filter, trapping gas, odors, and water contaminants when water passes through it. This is particularly beneficial in closed terrariums, where air circulation may be limited. By removing harmful substances from the air and water, charcoal helps to maintain a clean and balanced ecosystem within the terrarium [^1].

In addition to filtration, charcoal also improves the soil quality in a terrarium. It helps improve water retention in the substrate, preventing the soil from becoming waterlogged and creating a favorable environment for root growth. Charcoal’s porous nature allows it to absorb excess moisture, promoting proper drainage and preventing the onset of root rot [^5]. Furthermore, charcoal aids in maintaining a healthy balance of nutrients in the soil, ensuring optimal plant growth [^8].

Prevention of Harmful Growth and Odor Control

Another significant benefit of using charcoal in a terrarium is its ability to prevent the growth of harmful bacteria, fungi, mold, and mildew. Charcoal acts as a natural deterrent, absorbing potential plant pathogens, heavy metals, and toxic substances, which can be harmful to plant health. By inhibiting the growth of these harmful organisms, charcoal helps create a healthier environment for the plants in your terrarium [^1].

Charcoal also plays a crucial role in controlling odors within the terrarium. It absorbs foul odors that may arise from decaying organic materials, such as fallen leaves or dead plant matter. This prevents unpleasant smells from permeating the air, making the terrarium a more pleasant and enjoyable space [^3].

Charcoal Types and Usage

When it comes to choosing charcoal for your terrarium, it is important to select the right type. Activated charcoal, which is charcoal treated at high temperatures to make it more porous, is considered superior in terms of filtration and toxin absorption. It has increased binding capacities compared to non-activated charcoal [^1]. Activated charcoal is readily available and is commonly recommended for use in terrariums due to its enhanced filtration capabilities [^2].

Horticultural charcoal is another option that can be used in terrariums. While it may not have the same filtration potential as activated charcoal, it can still provide benefits such as improved air circulation and moisture control within the substrate [^6]. It is important to avoid using charcoal briquettes or used charcoal from stoves or fire pits, as these may contain additives, contaminants, and harmful chemicals that can be detrimental to the health of your terrarium [^1].

In terms of usage, charcoal can be mixed into the substrate or layered as a drainage material in a false bottom of the terrarium. By incorporating charcoal into the substrate, you ensure that it is in direct contact with the soil, maximizing its filtration and soil improvement benefits. A recommended approach is to create a one-inch layer of charcoal between the soil and rocks in your terrarium for optimal results [^2].

Long-Term Considerations and Alternatives

While charcoal offers numerous benefits in terms of filtration, soil improvement, and odor control, it is important to consider the long-term effects and maintenance requirements. Over time, the charcoal layer in your terrarium may become saturated and less effective in its filtration capabilities. As a result, it is good practice to replace the charcoal layer every 3-6 months or as needed [^2].

It is worth noting that while charcoal can provide significant benefits in terrariums, it is not absolutely necessary for the success of your DIY project. Many terrarium enthusiasts have achieved positive results without using charcoal [^4]. If you opt not to use charcoal, there are alternative methods for filtration and soil improvement, such as incorporating a traditional drainage layer using materials like pebbles or using sphagnum moss for slightly less dense filtration [^3].


In conclusion, charcoal is an important component in DIY terrarium projects due to its filtration and soil improvement properties. It helps filter toxins, control odors, prevent the growth of harmful bacteria and fungi, and provide a healthier environment for the plants in your terrarium. Choosing the right type of charcoal, such as activated charcoal or horticultural charcoal, and incorporating it into the substrate or as a drainage layer can help maximize these benefits. However, it is also important to consider maintenance and periodic replacement of the charcoal layer. Ultimately, the decision to use charcoal in your terrarium is a matter of personal choice and experimentation. With or without charcoal, your DIY terrarium project can thrive and bring joy to your indoor space.


[^1]: Terrarium Tribe (n.d.). Activated Charcoal for Terrariums: Is It (Really) Necessary? Retrieved from <a href=”https://terrariumtribe.com/is-charcoal-necessary-for-terrariums/“>https://terrariumtribe.com/is-charcoal-necessary-for-terrariums/](https://terrariumtribe.com/is-charcoal-necessary-for-terrariums/)
[^2]: Vivarium Vibes (n.d.). 3 Reasons Why Terrariums Need Charcoal (Plus helpful tips). Retrieved from <a href=”https://vivariumvibes.com/why-terrariums-need-charcoal/“>https://vivariumvibes.com/why-terrariums-need-charcoal/](https://vivariumvibes.com/why-terrariums-need-charcoal/)
[^3]: Hermit Garden (n.d.). Is Charcoal Essential for Terrariums? Unraveling the Truth. Retrieved from <a href=”https://hermitgarden.com/is-charcoal-necessary-for-a-terrarium-heres-why-its-not/“>https://hermitgarden.com/is-charcoal-necessary-for-a-terrarium-heres-why-its-not/](https://hermitgarden.com/is-charcoal-necessary-for-a-terrarium-heres-why-its-not/)
[^4]: Terrarium Station (n.d.). Is It Required to Have Charcoal in a Terrarium. Retrieved from <a href=”https://terrariumstation.com/is-it-required-to-have-charcoal-in-a-terrarium/“>https://terrariumstation.com/is-it-required-to-have-charcoal-in-a-terrarium/](https://terrariumstation.com/is-it-required-to-have-charcoal-in-a-terrarium/)
[^5]: Terrarium Station (n.d.). Activated Charcoal for Terrariums: Is It (Really) Necessary. Retrieved from <a href=”https://terrariumstation.com/activated-charcoal-for-terrariums-is-it-really-necessary/“>https://terrariumstation.com/activated-charcoal-for-terrariums-is-it-really-necessary/](https://terrariumstation.com/activated-charcoal-for-terrariums-is-it-really-necessary/)
[^6]: VivariumTips (n.d.). Why Is Activated Charcoal For Terrarium Necessary? Retrieved from <a href=”https://vivariumtips.com/activated-charcoal-for-terrarium“>https://vivariumtips.com/activated-charcoal-for-terrarium](https://vivariumtips.com/activated-charcoal-for-terrarium)
[^7]: Terrarium Tribe (n.d.). Horticultural Charcoal 101: Plant & Substrate Guide. Retrieved from <a href=”https://terrariumtribe.com/horticultural-charcoal/“>https://terrariumtribe.com/horticultural-charcoal/](https://terrariumtribe.com/horticultural-charcoal/)
[^8]: Terrarium Station (n.d.). The Benefits of Adding Activated Charcoal to Your Terrarium. Retrieved from <a href=”https://terrariumstation.com/the-benefits-of-adding-activated-charcoal-to-your-terrarium/“>https://terrariumstation.com/the-benefits-of-adding-activated-charcoal-to-your-terrarium/](https://terrariumstation.com/the-benefits-of-adding-activated-charcoal-to-your-terrarium/)
[^9]: Terrarium Station (n.d.). Do Terrariums Need Charcoal – Yes or No. Retrieved from <a href=”https://terrariumstation.com/do-terrariums-need-charcoal-yes-or-no/“>https://terrariumstation.com/do-terrariums-need-charcoal-yes-or-no/](https://terrariumstation.com/do-terrariums-need-charcoal-yes-or-no/)

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