Tarantula Humidity - Optimal Levels and How to Increase or Lower Humidity

Tarantula Heat, Temperature, Humidity – All You Need to Know

After you set up a terrarium for your pet tarantula, you need to learn about heat, temperature and humidity requirements for your pet tarantula. In this post, you will learn everything about a pet tarantula’s heat and temperature requirements, how to keep track of temperature, humidity, whether tarantulas need light bulbs and heating pads, optimal temperatures and humidity levels for different species, how to increase or lower humidity levels and more.

What temperature should a tarantula be kept at?

General optimal temperatures for a tarantula tank are between 70-85 Fahrenheit (21-29.4 Celsius). It’s however better to be in middle to the lower side of this temperature range. That’s because high temperatures can easily stress out a tarantula and cause dehydration and death. In general, never allow tarantula’s tank get warmer than 85 F (29.4 C), as it will cause serious implications.

  • Curly hair tarantula – 75-80 F (23.8-26.6 C) degrees temperature
  • Pink toe tarantula – 75-80 F (23.8-26.6 C) degrees temperature
  • Mexican red-knee tarantula – 75-80 F (23.8-26.6 C) degrees temperature
  • Chilean rose tarantula – 70-80 F (21-26.6 C) degrees temperature
  • Greenbottle blue tarantula (gbb) – 70-80 F (21-26.6 C) degrees temperature
  • Brazilian black tarantula – 65-80 F (18.3-26.6 C) degrees temperature
  • Arizona Blonde tarantula – 70-75 F (21-23.8 C) degrees temperature
  • Costa Rican Zebra tarantula – 70-85 F (21-29.4 C) degrees temperature
Tarantula Heating and Lighting Guide
A handheld thermometer

Make sure to check temperatures in your tarantula’s tank by placing at least two thermometers inside – one in the center and one near a burrow. You can use small thermometers with a probe like this so that you don’t need to have thermometers inside. Another great tool is a handheld thermometer like this, which helps check temperatures in any spot of the tank for more accurate readings.

Please note that generally, room temperatures are in the ranges that are optimal for tarantulas. And if you experience power outage or very cold night from time to time, most tarantulas will survive low 60s, and some even low-mid 50s (risky), if they can warm up the next day.

Tarantulas that are constantly kept at higher temperatures (78-80 F), are going to be more active and eat more, but might have a shortened lifespan. Same is for small spiderlings – higher temperatures might promote faster growth and reaching maturity.

Night time temperatures for tarantulas

Tarantulas can also survive some drops of temperature to 60 F (15.5 C) degrees for some periods of time. However, it should not be constant, as your tarantula will stop eating and become sluggish. However, drops in temperature to 68-70 F (20-21 C) are often tolerated well by tarantulas. That’s especially true for colder autumn and winter nights. But once again, tropical low-elevation tarantula species need warmer temperatures, at night as well.

When deciding whether night temperatures for your tarantula are too low, decide based on its origin. If your tarantula is from desert areas, then drops in temperatures at night are natural and are tolerated much easier.

But if your tarantula is from tropical area, then you should try to keep temperatures a bit higher at night. Many tarantula keepers don’t use any additional heating during day or night. But in general, tarantulas are very adaptive and hardy.

Day and night cycle for a tarantula? Do I need to use heat bulbs or heating pad for my tarantula?

Tarantula Optimal Temperatures - Do Tarantulas Need Light Bulbs and Heating Pads

If you notice that your tarantula is extra sluggish and doesn’t eat as much, it could be due to lack of heat. And if temperature in your house gets too low, lower than 60-64 F, especially in colder seasons, you might need to use additional heat.

However, it’s always better to use a space heater rather than heating the tank itself. The thing is, because most tarantulas are kept in small tanks, they can easily overheat and suffer from severe stress or death.

The problem with heating pads is that tarantulas dig the substrate to get away from heat, cool down and to sometimes stay warm. If you place a heating pad right under the tank, temperatures in the substrate will be too high. Tarantula won’t be able to understand that heat is coming from under, as it’s natural for them to dig.

Filtered light during the day and dark nights will be enough to stimulate day/night cycles for a tarantula. What is more, most owners don’t need any additional source of heat unless their home gets extremely cold.

However, generally avoid putting your tarantula’s tank in the garage or basement, near air conditioning or vents, or anywhere it gets too cold. Same applies for hot spots – anywhere with direct light should be avoided.

If for any reason you decide to use a heat pad, make sure to raise the tank off the table surface to prevent heat buildup and fire hazards. It’s important not to heat the whole tank with a pad, but only one part (1-4 or 1/3 of the tank’s surface + not under the burrow), so that there is a gradient of a warmer and cooler spot. This way, your tarantula can move to a warmer or cooler spot when it feels the need.

Avoid using heat bulbs as they cause overheating in small tanks. You can possibly use a red bulb (15 watts, over the tank) or LED lights of very small wattage during day and night. Red color seems not to disturb tarantulas too much, and can provide a better viewing experience. This is only to improve viewing experience. But in reality, tarantulas don’t like light and too much light will stress them out.

So to summarize, avoid using any bulbs or heating pads for a tarantula tank unless very necessary. If your room/house is cold, use a space heater instead. For example, you can use an oscillating space heater like this, and make sure to connect it to a thermostat. Thermostat will allow you to set maximum temperatures to avoid overheating the room.

Is it too cold for my tarantula?

You might understand whether it’s too cold for your tarantula not only by temperatures, but also its behavior. If your tarantula is eating less, not moving much at all, and even losing weight then it might be too cold for it. Another sign that your tarantula is too cold is when it spends most of the time on the warm side.

Do tarantulas need UV light?

No, tarantulas are nocturnal animals and don’t need UV light. However, not much research has been done on this. It’s better to feed a tarantula properly gut-loaded crickets so they get their nutrition from food. Read all about gut-loading here.

What humidity is optimal for a tarantula?

Tarantula Temperatures and Humidity - Is it Too Cold or Hot for My Tarantula

In the wild, tarantulas spend most of their time in a retreat, or a burrow, that has optimal humidity levels that they need. Some tarantulas dig their own burrows, while others take advantage of already existing burrows of various rodents. Their burrows also help them regulate their temperature, stay protected and hydrated.

Humidity is so important to tarantulas, that’s it’s one of the reasons why male tarantulas live much less than females. And it’s because when males leave their burrows to look for a female, they become vulnerable to dehydration while staying in temporary retreats.

The relative humidity inside a tarantula burrow should be around 60-80% and for some even up to 85%, and tarantulas require these levels to stay happy. Tarantulas from humid tropical locations require highest humidity level in their retreat.

Allow humidity levels in other parts of your tarantula’s tank to drop to drop much lower (40-50% in general). Let the substrate dry a little, and add some water to ONE corner around once a week. This is to avoid overly moist conditions, as well as bacterial and fungal infection.

Keep a watch on humidity levels with hygrometer with a probe like this. It’s better to use 2 hygrometers, one in a burrow and one on the other side of the tank.

Humidity levels for different tarantula species

  • Mexican red-knee tarantula – 60-65% humidity
  • Costa Rican Zebra (striped-knee) tarantula – 70% humidity
  • Brazilian salmon pink bird-eating tarantula – 70-85% humidity
  • Chilean rose tarantula – 55-65% humidity
  • Pink toe tarantula – 80-90% humidity
  • Curly hair tarantula – 70-80% humidity
  • Mexican red-rump tarantula – 65-70% humidity
  • Green bottle blue tarantula (gbb)- 60% humidity
  • Antilles pink-toe tarantula – 70-80% humidity
  • Leopard palm tarantula – 70-80% humidity
  • Aphonopelma tarantulas – 60-70% humidity
  • Mexican red rump (Brachypelma vagans) – 70-80% humidity

These humidity levels are for general guide only. Please remember that tarantulas are very adaptable to humidity levels in the tank, especially as they get older. Never rely or stress about humidity and temperature based on readings only, as they can be inaccurate. Humidity and temperature vary greatly throughout a tarantula’s tank.

It is always better to keep the tank dry + have a water dish. Unless your tarantula requires high levels, watch its behavior to get clues on how it feels. Tarantulas that climb the glass and go around the tank actively might need to have humidity lowered.

Humidity for tarantula spiderlings

Tarantula spiderlings will generally appreciate higher humidity levels. Make sure to add some water-retaining substrate and spray the enclosure with some water. This way, your spiderlings will drink water from the enclosure’s walls. You can also add some sphagnum moss that your spiderlings will use for their retreat.

You can read about top substrates for tarantulas here (new tab).

How to lower humidity in a tarantula tank?

To understand whether the humidity in the tank is too high, watch your tarantula’s behavior. Where is it spending most of its time? If your tarantula doesn’t spend most of the day in its retreat, then humidity levels are probably too high there. In this case, you need to lower humidity in the tank.

To lower humidity in a tarantula tank if it’s too high, you can allow more ventilation in the tank and let the substrate dry out a bit. If you have sphagnum moss, you might remove it for a while, until you get the levels in check.

How to increase humidity in a tarantula tank?

Pet tarantulas need humidity levels of around 65-70% in their burrows and you should monitor humidity levels with a hygrometer. However, humidity levels can be incorrectly measured, so don’t over panic. Watch your tarantula’s behavior for clues as well.

If your tarantula spends most of its time near a water dish and no in the retreat, then the humidity levels might be too low. There are some ways to increase humidity in a tarantula tank if it drops too low. These include:

Trick 1: Moisten the substrate

If the humidity levels drop too low in the tank, you can increase it by moistening the substrate in the tank. However, you don’t need to moisten too much substrate. Moisten only one part of the tank to create a gradient. Make sure not to use too much water, you should just dampen it.

Please remember that substrate will dry out from time to time, and you need to moisten it. It must not be seeping water, though. Once a week is often enough. Never spray water directly on your tarantula – it will stress it out. Don’t forget about ventilation – you don’t want any stagnant air inside the tank.

Trick 2: Add water to the water bowl

Adding more water to the water bowl will help increase humidity in the tank, as it evaporates. Make sure water bowl is always full and has some pebbles in it (to prevent crickets from drowning). Water will slowly evaporate and create additional humidity.

Trick 3: Add sphagnum moss

You can add some sphagnum moss in your tarantula’s tank if the humidity drops low. It’s a good idea to add the sphagnum moss like this into your tarantula’s retreat if humidity levels are low there. You can also add it to the corner of the tank.

Trick 4: Change substrate type

Using correct type of substrate is important to keep it humid in the retreat and the tank. Some of the best substrates include vermiculite and coconut fiber. Avoid using any sand, or peat and potting soil on their own – it will dry out quickly. If your substrate dries out quickly, it might be time to change it or mix it with another substrate.

Optimal temperatures for a tarantula’s tank are between 70-85 Fahrenheit (21-29.4 Celsius), and humidity – anywhere from 60-90%, depending on species.

Trick 5: Get a humidifier

If you live in a dry climate or heat your house a lot and use ventilation, your home might be too dry for a tarantula. Quickly drying substrate and low humidity levels might become dangerous for a tarantula very quickly. If humidity levels in your home are less than 30%, then you might decide to get a humidifier. Raising humidity to around 35-40% will create better humidity for your tarantula.

Trick 6: Add a plastic cover

Restricting some air movement from the tank will allow to retain more moisture in the tank, thus raising humidity. You can do this by covering a large part of the tank’s lid with a plastic wrap until humidity rises.

Important note about humidity

Even though most tarantulas require mid to high humidity levels in their tank, you should keep the cage dry in general. Allow the substrate to dry a bit before adding some water. This will ensure that you avoid fungal, bacterial and parasitic infections in your tarantula. However, if you notice any behaviors that indicate your tarantula wants more humidity, do what you need to increase for its comfort.

Thank you for reading the post! To learn more about tarantulas and their care, visit this page.