Next to feeding, the topic of substrates is the second most controversial subject in keeping crested geckos. There are certainly risks involved with substrate choices. Any type of particulate substrate (a bedding made of tiny pieces such as soil, sand, peat moss, coconut fiber, etc) can cause a health risk to your gecko – causing eye and skin irritations, choking hazards and impaction in the gut if eaten; or being too moist or too dry and resulting complications.
The purpose of a substrate bedding in a crested gecko enclosure is to help control odors and aid with cleanup (your benefit) and to provide proper humidity and a retreat for thermoregulation if the gecko gets too hot or cold (gecko’s benefit). We feel that paper towel is probably the safest and easiest substrate initially, but that a naturalistic soil mix is best overall substrate for most crested geckos. The main exception to this are hatchlings and breeding females. Because there is a risk of any gecko eating a particulate substrate, we don’t recommend it for hatchlings and juveniles under 8 grams.
Avoid any “litter” made for small animals. Most of them are definite impaction risks or otherwise not suitable for crested geckos. Specialty reptile “sand” such as Calci-sand is absolutely not appropriate for cresties or any animal.
Not all non-particulate substrates are safe or beneficial. Reptile carpet can harbor bacteria and mold as well as catch gecko toes or teeth as they chase prey. Artificial mulch mats are an attractive option, but they do not absorb moisture or odors so routine weekly cleaning (or more often) is a must. The same goes for shelf liners. Replace often. Geckos have been known to tear off and eat paper towel strips, which caused intestinal issues & prolapse but eventually passed from the body with time. Butcher paper might be a better choice as it is less easy to tear.
You will need to research different options to find the one that best fits the needs of you and your gecko.
We favor a natural soil substrate that retains water but drains well. When set up properly with plants and small invertebrate cleaning crew, naturalistic enclosures are self-maintaining, with only spot-cleaning or scrubbing of furnishings needed a few times a year, and regular glass cleaning with vinegar & water to maintain good visibility of your tank.
Terrarium Soil Mix
Many online retailers offer soil mixes that are excellent for home terrarium use. They contain a mix of soils and dry botanical ingredients, such as tree fern fiber (made from the roots of Cyatheaceae fern species. True “soil” is not good for terrarium use because it tends to compact and become soggy. The Atlanta Botanical Gardens of Atlanta, GA created the “ABG Mix” to allow aeration and host beneficial microorganisms that mimic natural cycles. The specialty mixes contain blends useful to orchid growers as well as reptile & amphibian keepers. This is the preferred mix for the health and beauty of a crested gecko display tank.
If you have a lot of tanks to fill, it might not be economical to order all of your supplies online or buy them at a pet shop. You can find some good options at local gardening centers and hydroponics stores, if you know what to look for – and what to avoid. Start with a good organic potting soil, topsoil or compost that doesn’t have added perlite, vermiculite, or wetting agents. Next, get peat moss or coco fiber (coir) to add a little more body and aid moisture retention. These are referred to as “soil conditioners”. Mix in 10-20% of washed play sand – the kind you can find for children’s sandboxes – to give variety to the particle size to avoid compacted dirt. You can change this mix to suit the conditions of your tank. A small amount of sand works well for temperate & tropical mixes, but for a desert animal you’d want to mix sand and soil and skip the soil conditioner as it will hold too much humidity or become dusty when exposed to dry climate conditions.
Mixing potting soil, compost or topsoil with a fibrous, plant-based material such as peat moss or coir will create an aerated medium to properly plant the tank. Peat moss is decomposed sphagnum moss harvested from natural bogs, many of which are home to threatened wildlife. Coco fiber, or coir, is the hairy part of coconut husks and is absorbent and expansive and is environmentally friendly. We do use both, but since peat fiber takes a very long time to break down, soil can be re-used after thorough rinsing and sunbaking to kill microorganisms. You can “solarize” soil by putting it in a black garbage bag and sitting it out in the sun for a summer, this should kill most bugs. If you’ve had a case of cryptosporidiosis or entamoeba, throw it out in sealed plastic bag. Don’t risk the lives of future pets.
Note that any particulate (tiny pieces) substrate can cause issues. Some people have had issues with peat or coir as they can both be ingested and swell in the intestine, causing impaction. Mixing it with the compost or soil reduces the risk. Here are some other tips to avoid impaction:
- Use a screen to sift our large particles
- Provide leaf litter cover and/or terrarium moss on top of the substrate.
- Don’t use with hatchling crested geckos
- Don’t feed live foods in the enclosure, or use a feeding dish
The coco fiber can now be mixed with sifted organic potting soil or compost so that it can support plant growth, as well as harbor a “cleaning crew” of springtails and isopods to breakd down solid wastes and micro-fauna to make the soil mix “bio-active”. This will greatly minimize cleaning and maintenance on the tank.
You can use straight coco-fiber but this can pose impaction risks as the fibers expand when wet, such as in the stomach or intestines if eaten. Mixing with small soil particles helps minimize (but not eliminate) the risk.