What you need to know is how to raise the humidity in a terrarium if you live in a dry area or take care of a species that needs a lot of it, like a rainbow boa or an amphibian species.
Terrariums allow us to create miniature worlds under glass, from lush jungles to arid deserts. But keeping these tiny biomes thriving requires balancing light, temperature, ventilation and humidity. For many terrariums, high humidity is essential for inhabitant health. Low moisture stresses delicate tropical plants and reptiles. Luckily, effective techniques can maintain needed humidity levels. Read on for tips to perpetually preserve that all-important dewiness within your terrarium.
Understanding Humidity and Its Importance
Before learning how to elevate it, we first must grasp the significance of humidity in terrarium environments
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Humidity measures the amount of water vapor suspended in air as a percentage. Higher values indicate more moisture.
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For tropical terrariums, ideal humidity ranges from 60-80% Desert setups require 40-50%
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Humidity impacts transpiration, respiration and growth for plants and animals.
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Low humidity stresses inhabitants. High levels increase disease risk.
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Glass walls naturally retain some moisture but levels still require control.
Creating and maintaining the preferred humidity range contributes greatly to terrarium health and vitality. Let’s explore methods for accomplishing this.
Technique #1 – Frequent Mistings
The simplest way to raise humidity is by regular misting of the terrarium interior, Some guidelines include
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Mist using purified water to avoid mineral buildup on glass and plants.
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Mist once or twice daily, aiming to moisten walls, decor, substrate and foliage.
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Time mistings to avoid wetting inhabitants at vulnerable times like night or while basking.
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Install an ultrasonic fogger on a timer for automated, consistent misting.
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After misting, allow ventilation to avoid excessively wet conditions.
Frequent misting provides immediate humidity but vapor quickly dissipates as wetness dries. Consistent repetition is key to maintaining humidity between mistings.
Technique #2 – Restrict Ventilation
Limiting ventilation helps retain moisture from misting or other sources:
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Cover all or most of wire mesh tops with acetate film, plastic or plexiglass.
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For openings, use movable strips to tweak ventilation as needed.
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Seal any gaps around lids or doors with non-toxic aquarium-safe silicone.
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Use substrate and materials that don’t allow excess airflow through the bottom.
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Strategically place plants, rocks and decor to block parts of vent openings.
Finding the ideal balance of ventilation takes experimentation. Enough air exchange is still needed to cycle fresh oxygen and prevent excess CO2.
Technique #3 – Include Water Features
Incorporating pools, waterfalls or drippers boosts humidity through surface evaporation:
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A recirculating fountain or waterfall releases fine mist when flowing down rocks or wood.
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Shallow pools and ponds with slow water movement have large surface area for maximum evaporation.
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Avoid deep stagnant pools, which increase risk of drowning for small inhabitants.
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Position water sources to avoid soaking substrate or over-wetting any section.
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Use an aquarium pump, auto-mister or drippers to keep circulation and moisture consistent.
Water elements raise sight humidity directly around them. Place near heat sources to maximize evaporation.
Technique #4 – Use Moist Substrates
Substrate composition and moisture content also impacts humidity:
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Pick porous media like coconut fiber, sphagnum moss, cypress mulch or orchid bark that holds moisture.
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Add water-retaining polymers like polyacrylamide gel to boost moisture retention in substrate.
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Use shallow depths of 1-2 inches to allow evaporation from lower levels.
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Pour water directly into substrate away from plant stems to wet from bottom up.
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Allow the top layer to dry out between mistings to avoid continual saturation.
In wet tropical terrarium types, the substrate itself can contribute substantially to humidity through evaporation.
Technique #5 – Choose Moisture-Loving Plants
Plant choices also affect humidity through transpiration:
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Select tropical species with high moisture needs like ferns, mosses, bromeliads and orchids.
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Avoid arid region plants like cacti and succulents which prefer drier conditions.
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Use epiphytes mounted on wood or rocks to maximize exposed surface area for transpiration.
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Maintain optimal plant health with lighting and nutrients so transpiration isn’t stunted.
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Propagate from cuttings for lots of young plants with high transpiration rates.
Additional plant growth translates directly into more transpiration and higher humidity. Dense planting with moisture-loving species boosts humidity naturally.
Technique #6 – Use a Cool Mist Humidifier
For terrariums without living inhabitants, a cool mist humidifier can automatically elevate humidity:
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Choose a small capacity humidifier sized appropriately for the terrarium volume.
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Use an adapter hose to direct mist directly into the terrarium.
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Place the humidifier outside and pass the hose through an opening via a grommet.
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Install a small fan to help distribute the mist throughout the enclosure.
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Use an external hygrometer to monitor humidity and set the humidifier accordingly.
While too involved for a simple terrarium, humidifiers offer hands-off automation for more complex setups.
Warning Signs of Inadequate Humidity
Monitor terrarium conditions to watch for these signs of insufficient humidity:
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Excessive drying or browning of leaf tips and margins on plants
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Increased wilting or loss of leaves
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Lethargy, dry skin or retained sheds in reptiles and amphibians
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Condensation only lasting a short period after misting
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Substrate drying completely within a day of watering
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Low humidity readings on external or internal hygrometers
Address such issues promptly before inhabitants become stressed and health declines.
Maintaining the Balance
The goal is reaching an equilibrium where humidity lingers in the optimal range between mistings and maintenance. This requires:
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Frequent monitoring with a hygrometer.
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Adjusting factors like ventilation, watering or misting frequency based on readings and plant/animal condition.
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Being willing to tweak the balance as lighting, temperatures and plants mature over time.
With attentive care and the right techniques, terrariums can thrive for years within their miniature world of ideal humidity.
If Cheap Hygrometers are Inaccurate, Are they even worth it?
I understand that you don’t want to spend the extra money on a more accurate hygrometer. I didn’t want to either. Fortunately, there is a way you can calibrate even the cheap units!.
Instead of a ziplock bag, I used a Tupperware container like in this video:
Note: You need to wait the full 24 hours, as the video says. Not 6 like the wikiHow article says.
It’s important to remember that the cheap hygrometer you bought won’t have a button that lets you change the reading it gives you. For example, this was my result after calibrating my units:
This meant that the white hygrometer was reading about the same as the black ones, which were reading about 2010-12-22% high. There is nothing I can do to the black ones to make them show the right number. Every time I look at them, I have to do some math in my head.
NOTE: I redid this calibration about 1 year later and the white one then displayed 72% (i. e. 3 % low) and the black ones displayed 79% (4% high). As I said above, over time the inexpensive hygrometers will fluctuate in their accuracy.
How to Measure: Best Hygrometer for Reptiles
Finally, I understand what relative humidity is, but how do you find it? Which hygrometer is best for snakes?
There are many digital hygrometers on the market, typically you can save money by buying one off of Amazon rather than your local pet store.
You have two options when it comes to hygrometers:
- They cost $3 to $8, and I use the two below. The white one seems to be more accurate; see below. Inexpensive hygrometers have two fairly serious faults. The first is that they aren’t very accurate, and the second is that they will get even less accurate over time because high humidity damages sensors over time.
- Or expensive ($10-25). You’ll find high-quality hygrometers in the cigar hobby. It looks like those guys really care about relative humidity! Cigar hygrometers are very accurate, can handle high humidity for a long time, and can be calibrated and recalibrated to keep their accuracy.
Increase Humidity In Your Enclosure
FAQ
What is the best way to keep humidity up in a terrarium?
How do I keep my reptile tank humid?
How does a terrarium affect humidity?
More plants = More transpiration = More water evaporation. If water is the fuel for your terrarium, then your plants are the engine to create humidity. So, the more full your terrarium is with plants, the easier it is to maintain that high humidity level necessary for tropical plants.
Do terrarium plants need high humidity?
Terrarium plants need high humidity levels to survive, so it is vital to maintain the proper humidity levels by minimizing water evaporation and air circulation, implementing an appropriate misting system, using a suitable terrarium substrate, etc. Keep reading for more tips on keeping a terrarium humid so that your plants can thrive!
How humid is a terrarium?
Most terrarium plants prefer humidity levels above 60%, while some enjoy as high as 80 or 90%! Therefore, indoor gardeners need to work to make sure that their terrariums stay more humid than the rest of their homes. How Do you Check Humidity Levels in a Terrarium? First things first — how do you know if your terrarium is humid enough or not?
How do you keep a terrarium humid?
To keep your terrarium humid, keep it in a warm, moist area of the home, mist it regularly, and keep it away from any fans or drafts that can dry it out. Devices like a hygrometer or a fogger can be great tools to help you monitor and regularize the humidity inside your terrarium.
