Best Ways to Remove Mould and Algae in Terrariums

Are you having trouble with mould and algae in your terrarium? While it’s natural to have some, for the long term health of your terrarium, it’s a great idea to prevent them from taking over.

Today, let’s talk about great ways you can remove and control mould and algae in a terrarium!

The Solutions

Here are the solutions to mould and algae, if you prefer reading instead.

1. Rubbing Alcohol

Dip a cotton swab in rubbing alcohol and gently wipe mould and algae off the glass and plants. It evaporates quickly after getting the job done. In my experience, this works like a charm and has yet to fry any of my plants, including sensitive moss.

2. Hydrogen Peroxide

Dip a cotton swab in diluted hydrogen peroxide and gently wipe mould and algae off the glass and plants. You can get this sold purely as hydrogen peroxide or as bleach.

If you buy it as bleach, check the ingredients and ensure it only says “hydrogen peroxide”, without anything else that might be harmful to your terrarium. Avoid chlorine bleach, which contains sodium hypochlorite.

I’ve had success with 1 part hydrogen peroxide to 3 parts water. You can start with less to be on the safe side and test in small spots. It breaks down quickly and safely into oxygen and water.

3. Physan20 or commercial specialty products

I’ve also had success with commercially sold products like Physan20. For Physan20, I’ve used 1 spritz from a ready-to-use bottle, diluted in 50ml of water and misted the terrarium with long-lasting results. However, for commercial products, less really is more. Go easy to avoid damaging your plants. I’ve had foliar damage from a pure application of ready-to-spray Physan20 before, and wouldn’t wish it on anyone else.

4. Opening the lid to let excess moisture evaporate

Opening the lid to let excess moisture evaporate can help lower the humidity level, introduce airflow and discourage algae and mould growth. Sometimes, a terrarium may be overwatered and this can help to balance the moisture level inside.

5. Springtails

Add springtails. They’re detritivores that munch on algae and mould, keeping your terrarium clean. Plus, they add a spice of life to your little landscape. In my experience, this is the most effective and long-term solution to mould and algae. You won’t have to clean the terrarium yourself as frequently. You can jump in for minor touch-ups if you’re a bit of a perfectionist.

Personally, I recommend keeping a stock of springtail culture separately and feeding them with baker’s yeast. You can transfer them into any terrarium that needs them. Once they are transferred into a terrarium, you do not need to feed anything additional. They will live off the terrarium itself and keep it clean. Unlike snails, they are safe for your plants.


Now, I hope these tips will help you with mould and algae, so you can enjoy your terrariums more! What are your favourite ways to get rid of mould and algae? Feel free to share in the comments.

Happy planting! 

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.