Why Does My Terrarium Smell? (Solutions + 3 Methods)

One issue that many owners of terrariums can potentially face is dealing with an odor coming from your mini-ecosystem. From time to time, we often encounter questions like “why does my terrarium smell so bad?” A simple solution is getting rid of the water, but let’s stop right there and analyze your situation before taking any steps.

At this point, you probably understand the cost of running a terrarium. But for those who don’t, then you can check out my recent article about the cost of running a terrarium, aquarium, and paludarium. Alright, let’s cut to the chase!

Scenario: You’ve spent hours and days growing your terrarium, but then one day, you suddenly smell an odor and you begin to wonder where it’s coming from. You investigate a little further and finally realized that the horrible smell is coming straight from your terrarium.

why does my vivarium smell
“What’s a solution to fixing my terrarium’s horrible smell?”

You’re lost, frustrated, and have no clue how you can fix this problem. As the hours and days continue to past, the smell coming from your terrarium becomes worst. You’re browsing the internet in search of a solution but couldn’t find any information that talks about the smell of terrariums. Your heart slowly breaks in half.

Fortunately, a good friend of yours shared this article with you or you’ve researched enough to find VivariumTips.com

If you’re one of those terrarium owners that put your ecosystem inside of your home, then you’ve probably moved it outside by now. If you’re reading this right now and have been frustrated because of the odor, then let me help you solve this problem and guide you into returning your terrarium back to the way it was before.

why does my terrarium smell bad
“Help! My terrarium is dying and it smells like rotten eggs!”

What’s causing the terrarium to smell like rotten eggs?

Reason: One reason for the terrible odor could be hydrogen sulfide which comes from anaerobic bacteria. This could mean that your terrarium is oversaturated with water which can lead to a build-up of anaerobic bacteria. Because of this, it can cause imbalance pH levels, rotting roots, sogginess of soil, and likely rise in toxic methane.

Solution: Your answer to fixing this problem is to get rid of the standing water at the bottom of your tank/jar. When owning a terrarium, one piece of advice that I can give you to prevent an odor is that you should have the substrate moist without any puddle of water on the bottom. By doing this, you can stop anaerobic conditions.

Terrarium in clear glass jar
“Why anaerobic, why must you do this to me?!”

If you take a closer look at your terrarium and notice that the false bottom is saturated with water to the point where it’s wicking into the dirt/soil, then you should eliminate any standing water and do a little mixing with activated charcoal within the substrate. Here is some advice after you remove the standing water from your terrarium:

Advice 1: You could always start with a moist substrate. When doing this, you can add a layer of moss along with the charcoal to block the dirt at the false bottom.

Advice 2: As a terrarium owner, you will not want standing water with more than a few drops when it comes to your false bottom. When you have heavy standing water, then it cannot be evaporated when it comes to a small terrarium. Having heavy standing water will eventually lead to a growth in putrefying and bacteria, which will unfortunately rot everything.

Advice 3: Instead of watering your terrarium, I would recommend that you use a spray bottle to create a mist. By doing this, you will likely be able to prevent pools of water.

terrarium prevent smell
Use a spray bottle to prevent over flooding in your terrarium tank.

Oh- What’s a false bottom, you asked?

What’s a false bottom in a terrarium?

A false bottom is when water drains pipes through the substrate and builds up in this drain layer, away from the substrate itself. Generally, most of the excess water that’s drained regularly is to avoid it from reaching the substrate.

Terrariums that have moist/humid conditions inevitably build up excess water in their substrate layers. This can result in water-logging, decomposing of the substrate, and expansion of an excess of anaerobic germs that can present a threat to the terrarium animals and plants.

dart frog false bottom

Dart frog lovers and enthusiasts who keep tree frogs generally use a “false bottom” to handle this excess water.

The example that can be provided here is the corner pond – this provides us simple access to the water table and it supplies a water body into which the bigger ranges of dart frog can transfer their freshly hatched tadpoles.

How do I get water out of my terrarium?

There are a few ways you can get unnecessary water out of your terrarium. If you have a terrarium stored in glass, you can use a drill. Another option is to purchase a long thin tube at your local pet store and drain out the water. You could even find drill pumps instead of using the long thin tube.

Method 1: You can use a drill to drill a hole into your terrarium tank/jar at the bottom to drain out the unnecessary water. After doing so, you can patch it up with something to cover the hole. If you don’t have a drill, you could always order your drill online here where shipping takes only several days. If this is out of your range, then you can continue to method 2.

Method 2: You can purchase a long thin tube at your local pet store or order your own online. After you have this product, find a large bucket or something to contain the water. Are you ready for the part where every pet owner hates the most? Stick one side of the tube into the water in your terrarium, then you will have to suck on the other end which will create a vacuum that’ll drain the water out.

Method 3: This method is probably easier than the others. What you can do is buy a drill pump online or at a store you can find. Similar to method 2, but you’re using a drill pump instead of your mouth. After you receive your drill pump, you can connect it to a drill and start pumping out water.

drill for terrarium
You can connect your drill pump to a regular drill.


Out of all the methods, I would prefer to go with method 3 just because it’s more efficient, clean, and less complicated. But you can use the method however you want as long as it’s in your best budget range.

From VivariumTips,


I’ve made it my duty to answer as many questions related to this guide as possible. If there aren’t any questions that are covered, feel free to comment and I will add it to this article to make it efficient for terrarium owners.

Overall, if this article helped you in any way, the best way to support this vivarium blog is to share an article with a friend. That’s all the support I’ll need. 🙂