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The Best Way to Deal With Horrible Fungus Gnats!

By Megan Christensen


Have you ever dealt with an infestation of fungus gnats? They are horrible aren’t they! They cloud up your terrarium and sometimes they escape from your terrarium into your house. 


Well we are happy to tell you our secrets about how to deal with them today!


In order for you to rid your terrarium and home of fungus gnats, you must first understand them and what contributes to the infestation.


Fungus gnats live in soil. Soils of any kind. If there is organic matter in the soil, there will likely be fungus gnats/eggs. Fungus gnats feed off of fungus and decaying organic matter which is abundant in any sort of soil. They love the speed at which things decay in terrariums because of the high moisture content. 


So the first step in mitigating a fungus gnats issue is to not put soil in your terrarium. Instead put a soilless substrate (base) like sand or activated charcoal. As long as your substrate has no decaying organic matter you will be free of fungus gnats.


The second step for making sure you reduce, if not eliminate, the number of fungus gnats in your terraria: always, always, ALWAYS wash your moss!!! 


Even if you bought your moss online, please still wash your moss. There almost always will be little bit of organic material left on moss after harvest. We try to wash it off as best we can before shipping to you, but you never know we might miss a spot. 


It’s super easy to wash moss! First grab a bucket and fill it full of water. Tanner almost always uses a 5 gallon bucket. 


Next grab your moss and submerge it fully. Massage on the bottom and the top to remove as much debris, soil, and organic matter. This include any leaves, grass, pine needles, and anything that is not moss. You can plant other plants with moss ins terrarium, but when washing moss you don’t want anything but moss. You can plant other plants in the terrarium later.


Next let it air dry for 30 mins at least. Then quarantine the moss by sealing it in a ziplock baggy. Leave it for at least 7 days and no more than 2 weeks. This is how you know if the moss is infested with fungus gnats, or if the moss is prone to mold. 


Now I’m sure you’re wondering, “well I have some in my terrarium already! How do I get rid of them?!” First and foremost you must quarantine the terrarium from all other terraria. This means put them either outside or in another room in your house. 


Next pick up some flying insecticide (we like hot shot) from your local store. This will NOT harm the moss. I repeat: it will NOT HARM YOUR MOSS. Spray a small amount inside your terrarium and seal it off for the next 30 mins. They should be dead by that point since there is no air flow. If they return after a week, spray once more with a different insecticide (containing a different ingredient). They should be gone for good after that. 


Tanner is a little passionate about this, I’m a little less zealous: pesticides aren’t harmful if they are used properly according to their instructions. They have undergone rigorous study and testing to make sure they will not hurt humans. Salt is actually more deadly than pesticides. It’s the misuse and lack of knowledge that causes people to get hurt or develop disease. 


Well, enough of that soap box!


We hope this has been helpful! Enjoy your fungus gnats free terraria and come back to enjoy more of our blog posts about moss and terraria!


Have you had struggles with fungus gnats? What strategies do you have for dealing with them? We’d love to hear in the comments!

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