Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Substrates for Reptiles


©1997 Melissa Kaplan


Substrates commonly used in reptile enclosures include those in the list below. Some of these substrates are inappropriate for some reptiles. Some are inappropriate for all reptiles and are included here so that you will be forewarned against buying them despite pet store recommendations and the implied or explicit wording on product packaging and advertisements.

Substrates should not be collected in the wild as the soil, leaves, sand, gravel, etc., may contain organisms that are harmful to your reptile. Even if you don't use herbicides and pesticides in your yard, these chemicals are transported through the air as both dry and wet deposits, and so contaminate soil, leaves, and the woody parts of plants, even those at some distance from the point of application.

Particulate substrates, even when made from "natural" or "biodegradable" products such as plant fibers, should not be used for any lizard who smells with its tongue. Particles become stuck to the tongue and are swallowed. Over time, they may build up in the gut causing a serious, even fatal, impaction.

Particulate substrates can be problematic for both snakes and lizards as it can become stuck to their hemipenes or everted cloacal tissues when they are defecating, being taken up into the cloaca when the tissue or hemipenes are retracted. This can cause injury and/or infection.

Some fine particulates may get into the eyes of lizards who have no moveable eyelids, causing irritation, injury, serious infection, or even blinding them. Small, sharp particulates may also scratch the protective covering of snake's eyes, which in turn may lead to infection.

Sometimes, the most convenient substrate is not the best substrate for the reptile. Many substrates are being marketed towards specific species even though they have demonstrated track records of causing serious illness, even death, for those species.

Naturalistic habitats may look natural and pleasing, but they are missing the key elements that allow the habitat to work in the wild. There are no decomposers, those invertebrates and microorganisms that do the work breaking down and recycling plant and animal wastes. This means that even naturalistic habitats must be regularly cleaned, including any plants that are contaminated with feces. When deciding whether to go with a naturalistic set up or a more artificial setup, keep in mind the greater amount of time, effort, and expense it will take to keep naturalistic environments clean and in control.



Fine Beach Sand
Available at aquarium stores or aquarium sections of large pet stores. May cause problems with reptiles who may pick up the fine grains with their tongues when lick-smelling or whose hemipenes or cloacal tissue are everted during defecation. To some extent, all sand carries this risk.

Playground Sand
When bought new (available in 50 lb. bags from hardware stores and large toy stores such as Toys R Us) this is a clean, medium-sized, rounded grain with some variation in the size and color of the grains. A good, all-purpose choice. A good conductor of heat. Suitable for larger desert species. Wet foods should be offered on sand-free platters or shallow bowls, or the reptiles fed outside the enclosure in an empty or paper towel-lined enclosure. Please note, however, that hatchlings/neonates of desert species should be kept on non-particulate substrate for the first 3-6 months or so until they are big enough to not experience problems with the sand.

Silica Sand
These densely packed fine grains do not conduct heat as evenly as the coarser playground sand. They can generate dust that, along with the fine sand particles themselves, stick to eyes, tongue, and body. Should be avoided for most desert and all other species.



Lava Rock
Not suitable for substrate or decoration. They are known to contain lead and so are frowned upon for use with any animal. In addition, they are extremely rough and can easily injure delicate skin and abrade shells, leading to bacterial and fungal infections.

Pea Gravel
Wash before using to remove dust. Good heat conductor. Generally used as the bottom layer to promote heat conduction and provide a bottom drainage layer when live plants and a soil top dressing is used.

Polished Stones
These are not suitable for substrate but may be used to add interest to naturalistic habitats. They may also be used to create, when securely glued together, decorative rocky walls and caves. They should not be used to create climbing walls for saxicolous lizards as they are too smooth for climbing. They can be used to form easily accessible "stepped" walls or outcroppings for climbing and basking. The problem with using them as a substrate is that they require copious amounts of water and time to thoroughly wash, disinfect, and rinse the disinfectant from them on a regular basis.


Wood and Paper Products

Orchid bark is available in plant nurseries. It is also being packaged and sold in pet stores for reptiles. While it is often used as the sole substrate, is it not a good conductor of heat, and is not comfortably burrowable by fossorial reptiles. It is not easily cleaned when kept with messy eaters or reptiles with wet fecal deposits and so must be frequently replaced. It is also ingested by some lizards and can cause serious, even fatal, impactions. Small amounts may be mixed in soil and sand substrates for reptiles for whom soil or sand is appropriate.

Butcher paper
Plain butcher paper may be used to line the bottom of enclosures. It is not particularly absorbent but is free of inks that may be harmful to reptiles. Large rolls may be purchased at restaurant supply stores.

Cypress mulch is available in many areas. Used alone for some reptiles, it is also suitable for mixing with soil to lighten it and provide a more attractive mix. It cannot be cleaned and so has to be removed and replaced with fresh mulch when soiled.

Newspaper (printed)
Layers of newspaper have been used for years in animal keeping. It is relatively absorbent when several layers are used, and inexpensive to replace. However, colored inks are known to be harmful to animals, and there may also be problems with the plain black ink. (Cedar shavings were accepted as a safe bedding for years before it was discovered that the volatile oils caused skin, respiratory and reproductive system damage.) In an enclosed space, an animal who relies heavily on olfactory and tongue chemosensation may be overwhelmed by the pungent odors of the inks, even the new soy-based inks.

Newsprint paper (unprinted)
Unprinted sheets may be obtained at stores selling moving supplies, or roll ends may be obtained from some newspapers. As with printed newspaper, it is relatively absorbent when several sheets are used, especially when layered with paper towels. Unlike printed newspaper, the unprinted sheets and rolls are not impregnated with potentially harmful inks.

Paper towels
Easily obtained and relatively inexpensive, paper towels make an excellent substrate for reptiles with belly injuries and those in the early stages of quarantine.

Aspen and pine shavings may be used for snakes and fossorial lizards. The shavings cannot be cleaned and so have to be removed and replaced with fresh shavings when soiled. At least once a month, all shavings should be removed and disposed of, and the entire enclosure cleaned and disinfected before new shavings are placed inside. Cedar shavings are toxic for all animals and should never be used in predator or prey enclosures. Cedar and redwood should not be used in constructing housing for any animal, nor in any furniture or paneling in a room in which any animals are housed.



General Precaution
Particulate litters are inappropriate for any lizard that uses its tongue for chemoreception. The litters become stuck to the tongue and are ingested. Even if such litters do not contain toxic chemicals, they may get stuck in the intestines, causing a rupture or impaction. They may also get stuck on everted hemipenes or cloacal tissue when the lizard defecates and so be taken up into the cloaca where they may cause injury or infection. Many litters are marketed as "natural" or "biodegradable;" some even claim to be "digestible" and "safe for use with reptiles." They may be made of natural materials such as wood, corncob, nut shells, and plant fibers, but this does not mean that they will be safely broken down and/or passed through a reptilian digestive tract. While some small pieces may pass safely through the reptile, experienced reptile vets can attest to the fact that too many become lodged in the gut, requiring surgery to extract - if the impaction is caught before it is too late.

Alfalfa Pellets
While not technically a litter, these alfalfa-based rabbit and small mammal food pellets may be used as a substrate for some lizards. The problem with these pellets is that, like the walnut shell litter, they quickly decompose and grow bacteria and fungi when they are wetted by food, water, feces or urates. They are unsuitable for chelonians, who may develop gait irregularities and foot deformities from trying to keep their footing on the highly mobile pellets. They are rather rough for burrowing snakes and smaller lizards. They may be used with green iguanas and prehensile-tailed skinks as they will break down in the gut if eaten and so will not cause intestinal impactions so long as the lizard is drinking regularly and eating moistened food. The pellets must be cleaned out as soon as they are wetted, however, or they will decompose and create an unhealthful environment both for the lizards and the students.

Cat Litter
Many of the litters made for cats are toxic to other animals. They are also very dusty and can cause respiratory and eye infections. These litters are also very dehydrating and will cause skin and other problems for any animal kept on them.

Clay Litters
These litters are unsuitable for reptiles. When ingested, they can cause intestinal impactions.

Corn Cob Litter
Along with the risk of impaction and injury due to accidental ingestion or uptake, corn cob can abrade the mouth of reptiles setting up ideal conditions for mouth rot (ulcerative stomatitis) to start. Pieces may also become lodged in the glottis of smaller reptiles and cause death by asphyxiation. Bacterial and fungal growths resulting from cob wetted by food, water, urates, and feces are common with corn cob and may cause illness or skin infections in the reptiles.


Lizard/Reptile Litters

Most reptile litters are just plant or other pet litters repackaged and marketed to reptile owners. They are made of wood shavings or compressed wood fibers, compressed recycled paper fibers, processed plant fibers, or clay. They are no safer for reptiles than other animal litters made of the same materials.

Paper Litters
May cause intestinal impactions if ingested. The dust may cause respiratory and eye irritations and infections. At least one brand causes almost an immediate respiratory inflammation in prehensile-tailed skinks (Corusia zebrata).

Walnut Shell Litter ("Desert Sand")
Largely nonabsorbent, these small, sharp particles are unsuitable due to the risk of injury and impaction if ingested. The litter provides a wonderful home for the bacteria and fungi that grow due to contamination of the litter by spilled food, water, urates, and feces.


Soils and Mosses

Sphagnum Moss
Sphagnum moss is suitable for use in parts of riparian, pondside, terrestrial and fossorial enclosures. It is moistened and kept damp to provide a microclimate of higher humidity. There have been some reports of animal keepers developing serious fungal infections from contact with spore-infected sphagnum moss. Moss should be periodically thoroughly dried out. It can be baked in a 250ºF (121ºC) for one hour.

Soil Collected from Outdoors
This is unsuitable for use unless you are taking some from where a wild-caught reptile was found and the reptile will only be kept for a day or two before being released at the site of capture. The soil and accompanying organic debris contains microorganisms, parasites, and environmental toxins that may be harmful to non-native species and to native species who have been in captivity for a long time.

Peat Moss / Potting Soil
This is soil or pulverized sphagnum moss that has been processed and sterilized. Bags of plain soil may be easily purchased at supermarkets, garden centers, building supply stores, and other stores with a large garden section. Read the packaging carefully to avoid buying those soils that have been mixed with fertilizers, herbicides, pesticides, vermiculite, or perlite. The latter two items may cause gut impactions if ingested, while the former are toxic to reptiles.

Spanish Moss
This may be wild-collected or purchased in garden supply stores. It should be baked (as described for sphagnum moss above) or frozen for at least one month to kill the chiggers that reside in it. As with sphagnum moss, it is suitable for use in small portions to provide microclimates or burrowable pockets for fossorial reptiles.



General Precaution
The glue used in most carpeting outgasses for several days, even weeks after installation. To ensure the safety of your reptiles, air out pieces that will be used in their enclosures for at least a week before installing it. When carpeting your home or school room, all animals, but especially birds and reptiles, should be removed to a safe location for 10-14 days until the rooms are completely aired out and toxic gasses dissipated. Even when using carpeting with special, environmentally friendly (less toxic, vastly reduced outgassing) backings, the animals should be removed for several days to let outgassing chemicals dissipate thoroughly.

Astroturf® / Artificial Grass
Astroturf® was the first artificial grass floor covering. Since then, carpet manufacturers have come out with many grades of artificial grass. Hardware stores and builder supply stores generally carry two or more grades. The least expensive is generally the best to use. It is more flexible, an important factor for thorough cleaning and disinfecting. The ragged cut edges may be folded under and basted to prevent fraying. Pieces can be washed and disinfected repeatedly before they require replacing. This substrate can be used for any terrestrial, arboreal, or fossorial reptile. It is cheap enough that several pieces can be cut for each enclosure and rotated each cleaning day. The pieces of artificial grass substrate sold in small, prepackaged pieces in many pet stores and mail order pet suppliers is the same as the product sold in builder supply stores.

Indoor/ Outdoor Carpeting
This product, also available at builder supply stores, looks more like indoor carpeting but is made for outdoor use as well. In its construction, it is more like the more rigid, more expensive grades of artificial grass and is difficult to clean and disinfect.

Household / Industrial Carpeting
With their deeper piles and very rigid backings, these carpets are difficult to clean and disinfect, and should be avoided for use as a substrate. They may be used to cover slick tubes or branches to create climbers for lizards (similar to cat trees made for cats).

Reptile Carpeting
These are fibrous, absorbent pads made in sizes to fit standard-sized enclosures. They wick the moisture away from the surface, but since most reptile deposits are solid feces rather than urates, this feature will not reduce cleaning time except for those species who deposit very dry, compact pellets. Expensive when compared to suitable household products.


Other Materials

Terry Cloth Towels
Terry cloth towels may be inexpensively obtained from thrift shops. They are easily cleaned and disinfected by machine washing in hot water, soap, and bleach. They are especially suited for reptiles in quarantine or with abdominal injuries.

Self-stick tiles may be inexpensively obtained from building supply stores. They may be grouted around the outside edges with aquarium silicone grout. Linoleum tiles are easily cleaned and disinfected and provide a durable flooring for large arboreal lizards and snakes.


Excerpt from Master's Thesis Classroom Reptiles, Sonoma State University, Rohnert Park CA. 1997

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Constipation in Reptiles

Constipation and Diarrhea in Green Iguanas

Use of Laxatives in Reptiles


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