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Monday, November 5, 2012

Moss Monday: Mold on Moss (Q & A)

Thanks to reader Kelly for her question on the post Prevention and Dealing with Pests, Fungus and Disease in Terrariums.

Question: My terrariums lately have grown a type of fungus and even tiny mushrooms. Will this kill my irish moss? Is there anything that can be done to "clean" the moss? Or is this harmless?

Answer: I do not think mushrooms could kill your moss but if the fungus is web-looking you may be facing trouble. You may try removing the fungus or mushrooms with tweezers or chopsticks to clean it out. Next time you build a terrarium you may want to wash the moss first and watch it for a few days before putting it in your terrarium.

To recap my general advice to prevent or at least minimize the chance of mold or pests appearing in a terrarium:

1.) Rinse all containers with a bleach/water mix before planting (with a day or two to dry out).

2.) Wash newly harvested moss and look for pests or unwanted plants in the chunks.

3.) Quarantine new plant specimens in a "holding tank" for a period of time so you can observe their behavior and adaptation to the terrarium environment.

Have you had problems with fungus or mold in your moss terraria?


  1. Hello! I have been reading your posts about how to prevent mold and I have tried them, but I keep getting that fuzzy white mold. At first I thought it was the rocks so I cleaned them in water/bleach and them boiled them before adding. But I got it again and this time I think it is the dried sheet moss I used for the filter. Is this common with dried sheet moss? Is there a particular brand that is recommended? I got mine form Lowe's in their garden department.

    1. It may be that your terrarium vessel is restricting air flow/movement in/out of your terrarium. You may want to try a bottle or jar with a wider opening, and keep a lid on it most of the time (maybe 75%) but remove it 25% of the time to allow air into it. Another problem may be that your terrarium vessel is simply to small. Does any of that sound possible?

    2. That restricted air flow is a possibility. I will try the 75/25 recommendation. Thank you!

  2. Hi, I am looking to start an open terrarium and love this site. It's fantastic.
    I've seen many people expressing their surprise about mushrooms appearing in their terrariums (often very beautiful ones in which the mushrooms look amazing) but am still a newbie. Are mushrooms always bad? I know it is important to avoid mold, but what is harmful? If we are mimicking an ecosystem where mushrooms naturally appear, are they supposed to be there?


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