Enclosure: Substrate

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“Substrate” is another word for bedding — the material used to cover the floor of your pet’s enclosure. Boas are semi-arboreal, which means that although they do like to spend time in trees and branches, they also spend time on the forest floor and will occasionally burrow. If your snake seems to have gone missing, double check the substrate — you might find a pair of mischievous eyes peeking out at you!

Boas should have at least 2” (5 cm) of substrate, depending on snake size, but thicker is better because it facilitates better burrowing as well as holds humidity more efficiently. Personally I prefer at least 3 inches.

Best boa substrates:

  • DIY mix (40% Organic Topsoil + 40% Zoo Med ReptiSoil + 20% Play Sand): This is arguably the best substrate option for boas because it is composed of natural materials least likely to contribute to impaction, smells nice, holds humidity well, drains beautifully, and is very cheap. One batch made with one bag of each fills a 4×2 base quite nicely.
  • Bioactive: Bioactive substrate is naturalistic substrate taken to the next level by adding detritivore insects (aka “clean-up crew”) which help break down waste and control bacteria and fungi. Bioactive substrates, if properly maintained, can go years without need for replacement. Join the Reptile & Amphibian Bioactive Setups group on Facebook for more information.
  • Terra Firma by The BioDude: Terra Firma is a bioactive-ready soil mix that tolerates higher temperatures and holds humidity well. It also holds burrows and tunnels well and does not require a drainage layer. Fairly expensive compared to the first option, but it lasts a long time and is well worth the investment.
  • Lugarti Natural Reptile Bedding: NRB is composed of a proprietary blend of natural materials to hold moisture well as well as control odor. Like the custom blend mentioned above, this substrate is reported to help prevent impaction. However this is definitely the most expensive options on this list.

Sphagnum moss and dead leaves are highly recommended for layering on top of substrate to provide variety and further enhance your enclosure’s ambient humidity. Plus, they make the enclosure look very naturalistic!

Boa Constrictor Substrate Options - young boa on reptichip bedding

Contributed by Jed Rice

Good boa substrates:

  • Cypress mulch: Smells nice, looks nice, and holds humidity well when you use a thick layer. Risk of impaction and/or intestinal damage for young snakes or if too much is ingested. Note that bags of mulch labeled as a “cypress blend” are not the same and not appropriate for use with reptiles.
  • Reptichip: Also known as coconut husk. Burrowable and well known for holding humidity well, but can only be ordered in bulk. Risk of impaction and/or intestinal damage for young snakes or if too much is ingested.
  • Coconut fiber: Cheap and holds humidity well, but it expands in the presence of moisture, which can pose an impaction risk if ingested in large quantities. It is also known to have problems with fungus and fruit flies, which can be annoying. It makes a decent alternative mix-in for peat moss with topsoil, though.

Okay boa substrates:

  • Aspen shavings: Cheap but can be dusty and only works if you don’t need help maintaining ambient humidity. Impaction risk.
  • Crumpled Newspaper/butcher paper: Inexpensive and sanitary, but not very absorbent and needs to be replaced frequently.
  • Paper towel or shop towel: Inexpensive, sanitary, and more absorbent than paper. Still needs to be replaced frequently.

Some keepers have made these substrates work, but I don’t personally use or recommend them. That said, paper and disposable towels make an excellent substrate for a boa in quarantine.

Bad boa substrates:

These substrates pose real risk to your boa’s health and/or are not absorbent or good for maintaining humidity. Never use these substrates for a boa.

  • Reptile carpet
  • Sand
  • Crushed walnut shell
  • Gravel
  • Carefresh rodent bedding
  • Pine/fir/cedar products

Boa Constrictor Substrate Options - young boa under leaf litter

Should you be worried about impaction?

Impaction is a condition where a reptile’s digestive tract gets blocked by foreign material. This is most often caused by substrate ingestion. However, wild reptiles ingest soil and sand all the time in their natural habitat, so why aren’t they dying from it?

Impaction isn’t only caused by substrate ingestion. It is also closely associated with low temperatures, dehydration, and large or expandable particles. This isn’t usually a problem for wild reptiles because they have adapted perfectly to the conditions of their natural environment. However when foreign matter is used as a substrate in captivity or we fail to provide sufficiently high temperatures or humidity, impaction becomes a problem.

If your temperatures and humidity are correct and your boa is otherwise healthy, you shouldn’t have to worry about impaction. However, it is worthwhile to take precautions where reasonable. Make sure your boa ingests as little substrate as possible during feeding, especially if your boa is young and if you are using a wood-based substrate.

How should you clean your boa’s enclosure?

Spot cleaning to remove feces and replace substrate soiled by urine should be performed often, at least once a week.

Deep cleaning should not occur more than once every 3-6 months. You can use an appropriate solution of vinegar, bleach, chlorhexidine, or F10 (in order from gentlest to harshest) to do so. Rinse until no fumes remain. Undiluted vinegar or lemon juice is particularly effective for removing hard water spots from glass.

Total substrate replacement should also be performed every 3-6 months as needed, unless your enclosure is bioactive. If your enclosure is functionally bioactive, years may pass between cleanings.

Although it may seem counterintuitive, reptile enclosures do not need to be deep cleaned every week or even every month. Sterile conditions weaken a reptile’s immune system, making it more likely to get sick, not less. The only time it is appropriate to clean a reptile’s enclosure frequently is if the animal is ill and/or in quarantine.


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
  7. Temperature Requirements
  8. Humidity Requirements
  9. Substrate Options ← YOU ARE HERE
  10. Enclosure Decor & Environmental Enrichment
  11. Feeding Your Boa
  12. Taming & Handling Tips
  13. Common Illnesses & Other Health Information
  14. Additional Resources