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Over the years, there has been a lot of debate among crested geckos breeders about the best type of enclosure substrate for rack setups. While some advocate for traditional substrates like paper towels, others have started to switch to soil substrates or even bioactive soil substrates that incorporate the use of micro fauna such as springtails and isopods. We recently made the switch to more natural substrates here is what we found.

The Bioactive Advantage

Bioactive enclosures have typically been only used by hobbyists or smaller-scale keepers while breeders tend to use plastic totes to maximize space and minimize costs. While there are some trade-offs and a significant difference in expense, the jury is still out on whether bioactive or natural enclosures offer benefits over a simpler approach. We decided it was best for our animals that we move away from using paper towels as substrate and will explain what has worked for us and how it might work for you too.

So what prompted us to rethink our husbandry? It started with a humidity problem. We’re located in the southeast and while ambient humidity may be an issue for keepers who live in more arid climates, a lack of humidity is famously not a problem for those of us in the southern United States.

We began noticing an issue with the humidity staying too high for too long in the plastic totes with paper towel substrate that we use to house hatchlings and sub-adults whereas the humidity in the few bioactive vivariums with natural substrate that we were keeping didn’t seem to have that issue. It has typically been advised that crested geckos should have their habitats kept quite humid (up to 80%) with a drying-out period in which it goes down to around 50-60%. Our issue was that in the totes, the humidity would go up after misting but stay high for days at a time before dropping out entirely. This required us to do less frequent misting in order to avoid the increased mold, bacteria, and shedding issues that come with housing crested geckos in too wet of an environment. While it is true that the natural climate of New Caledonia typically sees ambient humidity values of 70-80%, one has to keep in mind that this is in an open-air environment.

A closed micro-climate doesn’t really experience the natural airflow from wind that an open air environment would experience and within an enclosure of maybe a few hundred cubic inches, it’s not really possible to provide a range of humidity which is why a drying-out period is so important. In truth, most of us are over-misting our crested geckos.

The solution to our problem came from the difference we were observing in our bioactive vivarium. Initially, we thought it was an issue of ventilation so we first tried adding more venting to the totes to allow better airflow but this didn’t alleviate the problem. Additionally, the bioactive vivariums are glass enclosures with far less ventilation than plastic enclosures so it didn’t seem to be an issue of airflow. So what was the difference? The answer was in the substrate. In our bioactive planted tanks we use a modified version of what is commonly referred to as ABG mix. So we did some testing. We replaced the standard paper towel substrate with our own substrate mix in a select few of our subadult tubs and tested how they held up for a few months. The results not only fixed our humidity problem but also came with some added benefits that we hadn’t considered.

A closed micro-climate doesn’t really experience the natural airflow from wind that an open air environment would experience and within an enclosure of maybe a few hundred cubic inches, it’s not really possible to provide a range of humidity which is why a drying-out period is so important. In truth, most of us are over-misting our crested geckos.

A Humidity Problem

The problem with paper towels was essentially this: Either the enclosures were too wet or too dry, and there didn’t seem to be much of a middle ground. With a loose soil substrate, as long as you don’t mist it to the point of being oversaturated, the excess moisture is absorbed into the soil and naturally evaporates into the air inside the enclosure, creating a more natural process. Not only does this provide a more consistent environment, but it also takes care of a lot of other issues that come along with using paper towels.

  • Waste – Anyone raising tens or even hundreds of geckos knows how many paper towels the typical breeder goes through in a week. We are constantly searching for ways to minimize our waste not only for environmental purposes but also for cost-saving measures. A soil substrate eliminates this waste as well as lessens the frequency of cleaning. Typically when the animals have soiled their substrate, it required throwing out the old paper towels, wiping down or cleaning the tote, and replacing them with fresh paper towels, only for a mischievous hatchling to tread through its food dish and track it all over the enclosure within hours and requiring the process to be repeated. Not so with a natural substrate. Now all that is needed is a spot clean here and there and if you add springtails or isopods to the substrate, the process nearly takes care of itself.
  • Cost Saving – While switching to soil substrate has an initial start-up cost, the reduction in how many rolls of paper towels we go through has likely paid for the initial investment in just a few months.
  • Time Saving – Those of us with a significant size collection can spend an inordinate time cleaning cages each week. While we’ve not switched our hatchling tubs over to soil substrates and our adults were already in bioactive enclosures, changing a significant population over to soil substrate further reduced our time spent cleaning which means more time in the day for other aspects of our hobby as well as other hobbies. Essentially whenever you find yourself saying, “If only I had more time to focus on ____” anything that saves time in this hobby is a boon.

In Conclusion

The advantages of bioactive enclosures for crested gecko owners are evident. The shift from traditional enclosures to bioactive setups offers numerous benefits. One major advantage is the improved humidity regulation within the enclosure. Unlike plastic totes with paper towel substrate, bioactive enclosures maintain a more consistent humidity level, avoiding prolonged periods of excessive moisture. This helps prevent issues such as mold, bacteria, and shedding problems associated with excessively wet environments. The use of a loose soil substrate allows for natural absorption and evaporation of excess moisture, creating a healthier and more stable habitat for the geckos. Additionally, bioactive enclosures offer practical advantages such as waste reduction, cost savings, and time efficiency. The elimination of paper towel waste and reduced cleaning frequency contribute to a more sustainable and economical approach. With fewer cleaning tasks to perform, crested gecko owners can save time and allocate more of their day to other aspects of their hobby or personal interests. Overall, the adoption of bioactive enclosures provides a more natural and beneficial environment for crested geckos, improving their well-being and simplifying the care routine for their owners. For more on crested gecko care check out our guide here.


The above advice has not been evaluated by a licensed veterinarian. Results may vary depending on your husbandry practices and environment. We highly recommend extensive testing before adopting any new husbandry practices