Terrariums are beautiful, miniature indoor gardens that allow you to appreciate nature up close But the warm, humid conditions inside a terrarium also make it prone to mold growth While a small amount of mold is normal, too much can become a problem.
In this article, we’ll explore the most effective ways to deter mold in your terrariums so you can keep them healthy and enjoy their natural beauty.
Why Does Mold Grow in Terrariums?
Mold is a type of fungus that thrives in moist environments with decaying organic matter. Terrariums easily provide these ideal conditions for mold:
- High humidity from enclosed space and frequent misting
- Presence of soil, leaf litter, and dead plant parts
- Stagnant air lacking good circulation
- Poor drainage or overwatering leading to soggy substrate
Mold reproduces rapidly via microscopic spores that float through the air. Just a few spores landing on a suitable damp surface can start a new mold colony.
While a small amount of mold growth is normal as part of the terrarium ecosystem, too much mold can smother plants and make terrariums unsightly. So prevention is key.
10 Ways to Prevent Mold in Terrariums
Here are the top methods to stop mold before it becomes a problem
1. Use Activated Charcoal
Activated charcoal absorbs toxins and chemicals that can contribute to mold growth. Add a layer above the drainage layer or mix it into the substrate. Charcoal also removes odors and clarifies water.
2. Increase Air Circulation
Stagnant air promotes mold growth. Open terrariums or add small fans to increase air flow.
3. Control Watering
Overwatering leads to soggy soil, the perfect breeding ground for mold. Allow the soil to partially dry out between waterings.
4. Use Distilled Water
Tap water contains minerals and contaminants that can encourage mold. Filtered, distilled, or rain water is cleaner for terrariums.
5. Sterilize Hardscape Items
Boil or bake driftwood, rocks, bark, and other hardscape elements before adding to terrariums to kill any spores.
6. Use Springtails
These tiny insects feed on mold and help control populations. Their waste also fertilizes plants!
7. Apply Cinnamon Powder
Dusting cinnamon on the soil surface and on hardscape items can inhibit mold growth. It has natural antifungal properties.
8. Improve Drainage
A drainage layer of gravel, LECA, or charcoal covered with mesh prevents wet soil. Good drainage deters mold.
9. Bake the Soil
Heating potting mix in the oven at 200°F for 30 minutes kills any mold spores present before use.
10. Let New Terrariums Sit
Allow newly assembled terrariums to sit open for 1-2 weeks. This dry period helps prevent initial mold blooms.
What to Do if Mold Occurs
If despite your best prevention efforts mold still develops, take action to get it under control:
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Increase air circulation and allow the terrarium to dry out more between waterings.
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Spot treat visible mold with diluted hydrogen peroxide or alcohol on a cotton swab.
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Remove badly affected leaves and prune back plants with mold growth.
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Use a siphon or turkey baster to remove excess water pooled in the drainage layer.
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Apply cinnamon powder or a chamomile tea spray to inhibit mold.
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Introduce springtails to eat mold and keep it under control.
Be Patient and Persistent Against Mold
Don’t get discouraged if mold occurs despite your best efforts. Early intervention and persistently addressing contributing factors will get terrarium mold under control. Prevention truly is easier than dealing with a full-blown outbreak.
With attention to proper watering, air circulation, clean materials, and beneficial creatures like springtails, you can create a balanced terrarium ecosystem that keeps mold at bay. Remember, some mold is unavoidable, but you can minimize it to enjoy healthy plants and beautiful miniature gardens.
References:
Getting Mold In Your Terrariums? Follow These SIX Tips!
FAQ
How do I stop mold in my terrarium?
Is mold bad in a bioactive terrarium?
How do I get rid of mold mites in my terrarium?
How do you prevent mold from moisture?
How do you keep mold out of a terrarium?
Another way to reduce the risk of introducing mold into the terrarium is to use a substrate like coco coir, which is an eco friendly planting medium made from ground of coconut husks. The most effective way to keep mold at bay is to create a bioactive terrarium.
Can mold be prevented in a closed terrarium?
Mold can be prevented in a closed terrarium in several ways. You will not be able to avoid high humidity, but you can ensure good drainage of water. You have to prevent standing water in any case. On the one hand you can do this by using the wrong soil.
Can you get a moldy terrarium with healthy plants?
However, you can still get a moldy terrarium with healthy plants. Molds feed on sugars and other moist organic matter. They can even feed on surfaces like plastics if a biofilm (bacterial layer) is present. In my terrariums, I see mold most often on driftwood branches, and that’s totally normal.
Do terrariums get mold?
Mold spores seek out warm and humid climates. Mold is more likely to occur in closed terrariums than open ones. In a closed terrarium, the tank needs to be aired on occasion. Open terrariums naturally get more airflow contributing to mold prevention.