Enclosure: Lighting & UVB

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Boa constrictors do best with a 13:11 photoperiod, which means that they like 13 hours of light followed by 11 hours of darkness. During the winter months this can be switched to 11 hours of daylight and 13 hours of darkness. For best results, use a photoperiod of 12 hours light/12 hours dark during spring and summer for a more natural change between the seasons.

No light should be provided at night. Boas are nocturnal, and their eyes are evolved to see quite well in what humans perceive as total darkness. Providing a light source at night disrupts the snake’s day/night cycle and can negatively affect their health over time.


According to the UV Tool, Boa constrictor (and presumably other members of the Boa genus) is categorized under Ferguson Zone 2, which describes partial sun/occasional baskers, like most other snakes. The optimum UV index for boa constrictors is UVI 0.7-1.0. In large enclosures, T5 fluorescent UVB lighting is best used with a “sunbeam” method with areas of exposure no higher than UVI 3.0 contrasted by areas of partial to total shade provided by foliage, branches, and hides.

We recommend the following UVB bulbs housed inside a high output fixture with a reflector, mounted approximately 12” above the basking surface, and spanning half the length of the enclosure:

Ideally the intensity of the bulbs’ output should be measured with a Solarmeter 6.5, but considering that these are quite expensive, you can approximate the intensity by using the right type of UVB bulb and keeping the UVB source at the prescribed distance from the basking spot while you save up your money.

  • PRO TIP: T5 bulbs should be changed out every 12 months, while the T8 bulb wears out after just 6. Even though the bulb may still be producing light after that amount of time, that doesn’t mean that it’s still providing UVB. Write the date that you installed the bulb on one of the metal ends of the bulb to help you remember when it needs replacement.
Boa Lighting Guide - Boa imperator basking under UVB lighting

Is UVB required?

Most sources will tell you that UVB is not required for a healthy boa, and while they are right in saying that a boa will not die within a year if it does not get UVB exposure, this belief is minimalist and outdated.

Recent studies are supplying mounting evidence that UVB is beneficial for snakes’ long-term physical and mental health, and it provides one of the keys to maximizing a boa’s lifespan. In the interest of encouraging a higher standard of reptile care, we at ReptiFiles believe that some degree of UVB exposure should be available to any reptile species in captivity.


Keep reading:

  1. Introduction to Boas
  2. Members of the Boa Genus
  3. Red-Tailed Boa Shopping List & Starter Kit
  4. How to Select and Buy a Pet Boa
  5. Enclosure Size
  6. Lighting & UVB Requirements ← YOU ARE HERE
  7. Temperature Requirements
  8. Humidity Requirements
  9. Substrate Options
  10. Enclosure Decor & Environmental Enrichment
  11. Feeding Your Boa
  12. Taming & Handling Tips
  13. Common Illnesses & Other Health Information
  14. Additional Resources