How Long Can a Bearded Dragon Go Without UVB? (Period & Heat)

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Are you a newbie beardie owner and want to know if your bearded dragon needs UVB?

As a beardie owner myself, I will answer and explain the appropriate amount of UVB exposure and the effects of excess or insufficient UVB light exposure. Read more to learn!

Do Bearded Dragons Need UVB?

bearded dragon surrounded by tank's accessories

Bearded dragons need a high UVB output of between 10 to 12% [1]. The rays should be 12–14 hours a day. And you should feed your beardie enough calcium supplements to boost the UVB rays.

Take note: Bearded dragons are cold-blooded reptiles. They rely purely on UVB rays to warm their bodies and increase the ambient temperature.

Natural sunlight increases body temperature and activates vitamin D3. Your beardie will absorb natural sunlight rays during the day in the wild. But they revert to hiding after they have had enough sunlight.

As an expert, I recommend emulating their natural habitats. You should notice how your pet beardie appears to bask in the tank’s hot zone and cools down in the cool zone after a few hours.

READ MORE: How long can a bearded dragon go without heat?

How Many Hours of Light Do Bearded Dragons Need?

As a beardie owner, you should understand the number of light hours your bearded dragon requires. Here is a breakdown to help you understand more.

Do Bearded Dragons Need UVB All the Time?

Beardies do not require UVB rays all the time. But low UVB rays can lead to deficiencies in its body.

Two common deficiencies from insufficient UVB output include metabolic bone disease (MBD) and skeletal structure deterioration [2].

Enough UVB exposure is essential during the day. But your pet needs to rest and sleep at night. Thus, you shouldn’t leave the UVB lights on at night.

Here’s a video where you can learn more.

Pro Tips:

1. Always have battery-powered lamps ready in cases of a power outage.

2. Make schedule adjustments on the average tank temperature depending on the season. In the summer months, 8–10 hours of UV exposure is enough for your bearded dragon.

In the winter months, leave the lights on for 12–14 hours.

Read our answer to the question “Should I turn my bearded dragons light off at night?”

Will Beardies Get Enough Light Through the Window?

Placing your pet next to the window might seem like a great idea for them to absorb sufficient UVB. But remember that glass windows filter UVB rays. In fact, no glass allows UVB rays penetration.

When there is excess UVB in the tank, you will notice your pet climbing the walls of the glass tank. A habit is known as glass surfing [3].

Stress from feeling enclosed in a small tank or threat from its reflection will also cause glass surfing. So, it is not advisable to rely solemnly on the window as a source of UVB.

How Long Can a Bearded Dragon Go Without UVB?

A bearded dragon can go a maximum of 2 days without UVB. Insufficient exposure to light will cause vitamin D deficiency in the beardie’s body.

Expert tip: Make sure your beardie gets one hour of UVB exposure before breakfast. The UVB stimulates digestion.

Will a Bearded Dragon Be Okay Without UVB?

No. A bearded dragon will not be okay without sufficient UVB. Notice your beardie’s lack of appetite when she lacks sufficient UVB rays.

There are two reasons why a bearded dragon should not be without sufficient UVB. Bearded dragons need UV lighting for calcium formation in its body.

A beardie can suffer from calcium bone disease if she does not receive enough UVB light output. Enough exposure to UVB rays provides vitamin D3 to the beardie body.

Bearded dragons need adequate UVB rays (anywhere between 12 to 14 hours in a day).

These particular lizard species are adapted to the arid Australian desert, which receives increased heat output and light hours. Hence, always ensure that the beardie gets natural light during the day.

What UVB Light is Appropriate?

Today, you can find several artificial UVB solutions for your bearded dragon. UVB bulbs, however, differ in voltage, watts, and performance.

Thus, you need to know the appropriate bulb to consider for a beardie’s tank [4]. The lightning, for instance, should range between 290 to 320 nanometers, and provide 8 to 10% of UVB radiation.

Also, it is necessary to install a heat bulb and ceramic heat emitters in the tank during the winter months.

Expert Tip: Always ensure the type of bulbs matches the tank to avoid overheating. And always purchase recommended and the best UVB bulbs for bearded dragons.

Here are the ideal UVB alternatives I normally advise.

  • Heat bulbs – better than heat rocks.
  • Compact fluorescent bulbs – efficient and last longer.
  • Incandescent Heat bulbs – best for basking areas.
  • Mercury vapor bulbs – produce both heat and UVB rays.
  • Ceramic heat bulbs – produce heat only.

Other brands like Flukers, Reptisun, Exoterra, and Powersun are also top recommended choices.

Warning: Radiation bulbs, coil bulbs, and red daytime lights are harmful to these particular reptiles.

This video will show you more about this.

Bearded Dragon Light and UVB Considerations

There are a few significant concerns for the bearded dragon light and UVB. Here are three decisive factors to always consider.

1. Is it Ok for Your Bearded Dragon to Get the Warmth of the Sun Outside?

For a fact, the sun rays will only heat the beardies habitat setup. The sun’s rays will make the terrarium extremely hot for your bearded dragon to handle.

Extreme exposure to the sun’s heat has negative effects on the beardies skin. So, it is okay for your pet to get the warmth of the sun outside. But under supervision.

2. What Happens if You Forget to Turn Your Bearded Dragon’s Light on?

If you forget to turn your bearded dragon lights on, you risk affecting the dragon’s health. A bearded should not go 2 days without UVB.

Insufficient UVB light will cause vitamin D deficiency in the beardie’s body.

3. How Many Hours a Day Does a Bearded Dragon Need a Heat Lamp?

First, understand the appropriate UVB radiation source distance from the beardie’s tank. As an owner myself, I always ensure the UVB lamp is not too close to the dragon.

This prevents overexposure to UVB radiation. To create the appropriate environment in bearded dragon enclosures, here is what I recommend.

Install a basking spot/hot side of 29–43◦C (85–110◦F) and a cool-off side of 23–27◦C (75◦F–80◦F) for a baby dragon.

Have a basking area/hot side of 31–43◦C (95–110◦F) and a cool-off side of 25–29◦C (80◦F–90◦F) for juvenile and mature dragons.

And create a cool side of ¼ portion of the tank for your pet to cool down — meaning the bulb should stretch ¾ area of the enclosure.

Do not place any obstacle between the UVB light and the bearded dragon.

To learn more, you can check our guide about how much UVB does a bearded dragon needs.

And in this video, you can watch more about this.

The correct positioning of your lighting should be overhead to replicate direct sunlight rays. Avoid positioning a reptile bulb on the sides of the tank.

Inaccurate lamp positioning leads to incorrect light emission. So, the average distance of the light bulb from the terrarium should be about 12 inches.

But, some full spectrum light bulbs produce excess heat and should be placed further away from the tank.

My Pro Tips: Always counter-check with the manufacturers’ instructions before installing the light bulbs [5]. Ensure your beardie gets 12 hours of adequate heat.


Should I turn my bearded dragons’ daytime light off at night?

Yes. You should turn off the daytime light at night for approximately 12 hours per day. Beardies need a quiet and dark environment to sleep peacefully.

How can I keep my bearded dragon warm without a heat lamp?

cleaning a beardie

You can keep a bearded dragon warm with or without a heat lamp. I use an external source of heat.
You can pick full spectrum UV lights, incandescent electric lighting bulbs, or ceramic bulbs to produce sufficient heat. Alternatively, I place hot water rubber bottles in the beardies terrarium.

Why have a UV light if my beardie hides under her log every time I turn it on?

A UV lamp is essential for a bearded dragon. If you notice your beardie hiding under her log after turning the lights on, she is probably stressed by the general surrounding.
So, you need to adjust the tank’s layout and use the recommended UV output.

I turned off the bearded dragon UVB light for two days. Is it okay?

Yes. A bearded dragon can go two days without UVB light. However, ensure that you are using the recommended light bulbs for increased performance.

How much light for my baby bearded is needed?

batch of baby bearded dragons

A baby bearded requires the same amount of light as a mature bearded. The average exposure time for a baby bearded should be 12–14 hours of UVB. 16 hours during winter is recommended.


So, how many hours of light do bearded dragons need? According to this research, a bearded dragon needs 12-14 hours of light. Similarly, your pet beardie can go two days without light.

However, it is recommended to balance between appropriate light cycles. Always remember to switch off the basking light at night if you are using artificial light bulbs

beardie looking above

So, how long can a bearded dragon go without UVB? Let us know your opinion below!


  • 1. Royal Society for the Prevention of Cruelty to Animals. Bearded dragon CARE SHEET ENVIRONMENT [Internet]. 2019. Available from:
  • 2. Animal Care Hospital. MBD In Bearded Dragons [Internet]. 2021 [cited 2022 Feb 4]. Available from:
  • 3. Briggs H. Bearded Dragon Glass Surfing: Why They Do It [Internet]. Reptile Direct. 2020 [cited 2022 Feb 4]. Available from:
  • 4. NC State Veterinary Hospital Exotic Animal Medicine Department. Caring for Your Pet Bearded Dragon [Internet]. Available from:
  • 5. UVB Reptile Lighting – Terrarium Lighting [Internet]. The Bio Dude. [cited 2022 Feb 4]. Available from:
Alina Hartley
Alina Hartley

Alina Hartley is a small-town girl with a ginormous love of bearded dragons. It all started with Winchester, a baby bearded who was abandoned at the shelter by his former owners because of a birth defect that caused one front leg to be shorter than the other. Alina originally went to the shelter looking for a guinea pig, but one look at Winchester and it was love at first sight. From that day on, Alina has dedicated her life to learning everything she can about bearded dragons. She loves helping new beardie parents start their incredible journey with these magnificent reptiles.
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