Why Does My Terrarium Stink? How To Get Rid of It

Last updated on April 15th, 2023 at 03:54 pm

I know what’s going on in your mind. It’s “why does my terrarium stink?”, right? Terrariums are beautiful additions to any home, but it may be time to get rid of them if they smell bad. Several factors can cause terrariums to stink. Here are some tips for keeping them smelling good.


Why Does My Terrarium Smell?

The terrarium smells terrible due to anaerobic bacteria, fungi, and mold. They produce foul odors due to their low oxygen requirements. It can permeate substrates and even the air inside terrariums. Water vapor and humidity can also cause a stink in enclosed or glass terrariums.

In addition, anaerobic bacteria, fungi, and mold will spread to new places if your terrarium loses any of its substrates. Open-air Terraria can have foul odors due to mold growth and animal feces accumulation. You might smell bad in your terrarium for some of these reasons.

Anaerobic Bacteria:

Anaerobic bacteria produce bad smells due to their low oxygen requirements. Keeping your Terrarium at a low humidity level will encourage its growth. Additionally, if your Terrarium has a loose substrate, the anaerobic bacteria will spread to new areas.


Because fungus thrives in environments with low oxygen levels, terrariums often smell like fungus. A variety of fungi are responsible for the growth of molds, including Aspergillus and Rhizopus.


When dampness and humidity are abundant inside or outside the terrarium, mold can grow. In some cases, mold produces an overpowering musty smell which can produce a lingering smell.

Losing substrate:

Losing the substrate of your terrarium will also cause the anaerobic bacteria, fungi, and mold to spread into new areas. Decomposing organic material or gasses may cause bad odors.


In terrariums, too much water vapor can also cause odors as it promotes mold growth and other damp-loving organisms. Rotting plants, however, also attract insects, which can spread the odor to other areas of your terrarium.

Excessive light:

Artificial lights emit ultraviolet radiation (UV). That can damage terrariums, resulting in their eventual collapse. As a result, damaged substrates may release volatile chemicals which may cause smells to increase.

Changes in temperature:

Temperature changes can cause substrates and terrarium walls to expand and contract. This can lead to cracks or other openings in the enclosure that allow moisture and smoke from fires to enter. The release of gasses from decomposing materials can cause an increase in smells.


Are Terrariums Supposed to Smell?

Terrariums are not supposed to smell normally. However, terrariums can sometimes smell bad if their natural environment breaks down. So, terrariums that are healthy and perfect should not smell.

Their goal is to be as odorless as possible in order to promote healthy growth in your plants. While some people find soil’s smell pleasant, most users prefer it without fragrance. This reduces airborne allergens and improves indoor air quality.

Your terrarium may start to smell bad for one of the reasons listed above, however. Clean the terrarium thoroughly and replace any lost substrate or plant material if you notice a persistent odor.


What’s Causing the Terrarium to Smell Like Rotten Eggs?

In terrariums, hydrogen sulfide and decomposition are the most common causes of rotten egg odors. Air quality and humidity levels can also contribute to this problem. Hydrogen sulfide gas can accumulate in terrariums due to the high humidity levels and plants.

These pockets will eventually release sulfur-containing compounds, which will give items in the terrarium an eggy smell. Let’s find out how this issue causes rotten egg odor.

Hydrogen sulfide:

Some organic matter produces hydrogen sulfide naturally when they decompose. Water can also generate sulfur dioxide if it reacts with sulfur-containing compounds in soil or other materials. They release rotten egg odors when they reach high levels.


The decay of plants and substrate can also cause a terrarium to smell like rotten eggs. The organisms that consume plants and soil produce gasses that give off an eggy odor as they consume the materials.

Bad air quality:

Last but not least, a terrarium can smell like eggs if it has poor air quality. In terrariums that are full of pollutants, smells will rise up and be concentrated in areas such as the substrate.


How Do I Get Rid of the Smell in My Terrarium?

If your terrarium begins to smell bad, you may need to clean it thoroughly and replace any lost substrate or plants. By adjusting the humidity levels or opening some of the doors, you can also improve the air quality in your terrarium. The following instructions will help you get rid of the smell in your terrarium:

Clean the terrarium thoroughly:

There will be more smells in a dirty terrarium. Therefore, you should thoroughly clean it before replacing lost material or adjusting the air quality. The first thing you should do is clean every surface of the terrarium with a good terrarium cleaner and water. Before adding new substrate or plants, make sure everything is dry.

Improve the air quality:

You may need to add mechanical ventilation to your terrarium if changing the environment doesn’t eliminate the smell. The best way to do this is to open up some doors along one side or top and install an exhaust fan along with a good filter system.

Add a layer of fresh sand:

If you add a layer of fresh sand to the bottom of your terrarium, it can be very effective at absorbing and trapping the smells. Make sure, however, that you do not add too much sand, as it may become heavy and hard to move around if you do.

Add charcoal to the terrarium to absorb the smell:

You can add charcoal to your terrarium to absorb and trap smells. Maintain a tight grip on them and make sure they do not escape. It is important not to layer your charcoal too thickly or too heavily. Don’t add toxic substances like paint or artificial fragrances to the charcoal, for instance.

Use a terrarium deodorizer:

You can try changing the environment or adding charcoal if those don’t solve the problem. Alternatively, if nothing else works, you may need to use a terrarium deodorizer. Read the instructions carefully before using these products, since they are designed to mask and eliminate odors.

Mulch your terrarium:

The following solutions may not work for you, so you may want to consider mulching your terrarium. This is the process of adding fresh organic matter to the bottom of the terrarium (such as leaves, bark, etc.). It will also provide nutrients and moisture for your plants, as well as anchor and absorb smells.

Check for leaks:

Trying none of these solutions may not work, so you may want to look for leaks in your terrarium. You can check for swelling or wetting around the edges by removing the top and sides. To prevent additional damage, you should take corrective action as soon as you notice any signs of a leak.


Final Thoughts

The terrarium can smell due to anaerobic bacteria, fungi, excessive lighting, and a loss of substrate. Although terrariums are not supposed to smell, hydrogen sulfide can cause them to smell like rotten eggs. You can get rid of the smell of the terrarium by cleaning the cage often, changing the air quality, or adding terrarium cleaner.