While most tarantula species need moderate to higher humidity levels in their retreats, humidity levels that are too high can cause parasitic infestations and sickness in your tarantula. High humidity levels can also make your tarantula uncomfortable with the substrate and climb the glass more. In this post, you will find information what to do if humidity in your tarantula’s tank is too high and how to lower humidity in the enclosure.
What are optimal humidity levels for tarantulas?
In general, tarantulas need humidity levels varying between 60-80%, even higher for some, such as Pink toe tarantulas. These humidity levels should be near a tarantula’s retreat, or hide, where it spends most of its day. The rest of the tank should be dry.
Make sure to keep humidity levels in check by having at least one hygrometer in the hide, and one on the other side of the cage. Using hygrometers with probe like this will allow to put only probes inside the tank. Having said that, never rely on hygrometer readings to make your decisions. Keeping the tank dry and supplying some humidity to the retreat area is often enough for most tarantulas.
While proper humidity is one of the most important things for a tarantula’s well-being, very high levels can also be damaging. If humidity levels are too high, this can cause mites, nematodes, bacteria, and fungi in the substrate and generally make your tarantula uncomfortable. Air humidity should not be in the same range as 60-80%, it should be lower.
Generally, to keep humidity at optimal levels, some keepers only need to overflow their water dish once a week or so. For some keepers, there is a need to add some water to a corner of the tank and mist the tank once to twice a week. Humidity levels in the tank will depend on many factors – where you live, heating, tarantula species, temperatures etc.
Who needs to take more care of humidity for a tarantula’s tank?
Overall, you might need to take extra care about humidity if your tarantula is naturally a swamp dweller (Theraphosa genus for example). Or, if you live in a hot, arid place, such as Arizona, Texas etc. Also, if you live anywhere with high elevations (Idaho, Colorado, Nevada, New Mexico, approximately 5,000-6,000 ft), then drying of the air can lower tank humidity levels.
If you live in colder, temperate zones, such as cities of Canada, Northern USA or Northern Europe, you might experience lower humidity in winter in a tarantula’s tank. That is due to use of heating devices and home heating in general. If you use lots of heating, this might dry the air and cause low humidity.
Apart from these extremes, room humidity levels are often optimal and you don’t need to stress yourself too much. Tarantulas also adapt to humidity levels.
Tarantula behavior and humidity
You need to be more mindful about humidity levels if you have tarantula species that don’t like high humidity, such as a Chilean rose tarantula. They don’t like excessive humidity and feel uncomfortable on wet substrate.
If you see your tarantula climbing the glass more and being generally more active, it could be that humidity level in the tank is too high. A tarantula that spends most of its time near a retreat and water dish either likes high humidity or needs more humidity in the cage.
Humidity ranges are only approximate, sometimes tarantulas prefer lowest or highest number in the range. Observe your tarantula’s behavior for clues on how to alter humidity in the tank.
How to lower humidity in a tarantula tank when it is too high?
Now, let’s see different ways of how to lower humidity levels in a tarantula’s tank. Make sure to only change one thing at a time, as you don’t want humidity levels to drop suddenly and significantly. This can be detrimental or even deadly to a tarantula.
While you understandably take humidity and temperature seriously, please note that both humidity and temperature in a tarantula tank are very variable, and you shouldn’t rely on readings alone. Tarantulas are very adaptable (especially as they grow older), and it’s better to keep the cage dry as opposed to wet to prevent any infestations.
Tip 1. Allow proper ventilation to lower humidity
If your tarantula’s tank doesn’t get much fresh air or if you cover the tank with a cloth or wrap, then you should allow more ventilation. Poor ventilation and high humidity are a very bad combination. In these conditions, mold, bacteria and fungi start multiplying very fast. Mites can also infest the substrate with poor ventilation.
If you keep your tarantula in a custom tank, you might need to make extra ventilation holes. But make sure not to make holes too small, so that your tarantula’s fangs don’t get stuck in them. Diagonal ventilation and ventilation from bottom to top are optimal. They are also better than holes on one side only or incoming or outgoing air on one side of the tank (see the picture above).
More ventilation will allow the bottom substrate to dry out more, thus lowering humidity in the tank. Another way to improve ventilation is to use a small fan, but positioned very far from the tank. Avoid using air conditioning in a room with a tarantula. Make sure to monitor humidity levels in your tarantula’s retreat, though.
Tip 2. Stop misting the tank
In general, to keep humidity levels in check, it’s advised to mist the tank once-twice a week. Never mist your tarantula directly, though. This can cause stress and water droplets will trigger its sensory hairs. If you wish to lower humidity levels in the tank, try to reduce misting if you do it, or stop it completely.
Generally, it is enough to overflow a water dish once a week or so, to keep humidity in check. If humidity levels get too high, don’t add water to the substrate and keep it dry.
Tip 3. Move your tarantula’s tank to a different room
If your tarantula’s tank is in a room that is cold and has high humidity levels, you can move it to another room. Generally, basements and garages tend to be colder or have higher humidity levels. You can check your room’s humidity level by using a room hygrometer like this one.
As discussed above, heating and air conditioning also lower humidity greatly. Sometimes, heating and air conditioning make the room and a tarantula’s tank too dry. So, if you review humidity levels in different rooms of your home, you might find that moving your tarantula’s tank makes a great difference.
Tip 4. Use a dehumidifier
If humidity levels in your house or room are too high, you can try using a dehumidifier to see if it makes any change. Some of the most humid places in USA include Los Angeles, Florida, Houston, Portland, Miami and many more.
And if you live somewhere where it’s both cold and humid, then you might benefit from using a dehumidifier not only for a tarantula, but even for yourself. Make sure not to overdo it though, and monitor levels in your home and the tank so that you don’t cause drastic changes.
Conclusion on lowering humidity in a tarantula’s tank
To conclude once again, you should not rely on thermometers and humidity gauges alone to tell you of ideal temperatures and humidity levels. Humidity levels are only for general guidance. Instead, keep the tank and substrate dry (for most species) and overflow the water dish or wet the corner of the tank depending on needs.
Do not stress about humidity levels, as most keepers normally have optimal levels and temperature at home. However, make sure to research specific needs of your tarantula species. Watch your tarantula’s response to humidity and make decisions based on that.