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  • Writer's pictureKarina Schulz

Loose Substrates and Impaction

Is loose substrate safe to use? It can be confusing when selecting a substrate or changing to a new substrate to sift through myths and facts. Typically, reptile keepers are advised to avoid all loose substrates due to the risk of impaction in their pets. When used incorrectly or when using the wrong kind of loose substrate, this may be true. However, when using a naturalistic substrate alongside correct husbandry, the risk of harming your reptile is quite low.

Terry the leopard gecko on Reptile Ready Arid Mix


What is impaction?

Impaction is a blockage in the digestive tract, caused by the ingestion of unsafe materials, food that is too large, and most often, a side effect of an unhealthy reptile or improper husbandry. Dehydration, caused by humidity that is too low or lack of water, low basking temperatures, and nutritional deficiencies are all examples of health issues that can contribute to a reptile becoming impacted. The most obvious symptom of impaction is noticing that your reptile is constipated or has difficulty passing feces. This may be accompanied by lethargy and a lack of appetite.

Impaction is the concern that comes to the mind of most keepers when discussing loose substrate, since there is the potential for it to be consumed by the animal. Some loose substrates, most notably calcium sand (sold as calci-sand or vita-sand), are known to lead to impaction. As its name implies, calcium sand contains a high level of calcium, which encourages the reptile to eat it in large quantities. The sand itself clumps when wet, making it easy to compound in a reptile’s intestines. For this reason, calcium sand is a substrate that should be avoided. Since naturalistic substrates would not contain high levels of calcium or vitamins, the reptile may only accidentally consume a small amount while catching prey. In a healthy reptile, a small amount of dirt can be passed when they have access to water and proper basking temperatures.


What is a naturalistic substrate?

In simple terms, a naturalistic substrate mimics what the ground would be like in a reptile’s natural habitat. This helps promote behaviours such as burrowing or egg laying in female reptiles. Live plants and microorganisms can be added to these substrates as well to help create a bioactive terrarium for keepers interested in further mimicking their pet’s natural environment. We recommend Reptile Ready bioactive substrates as they are hand-sifted to ensure there are no harmful particles included in the substrate. In addition, their substrates are free from harmful fertilizers and instead, they use insect frass (poop) to provide a safe and natural fertilizer for live plants.


What is found in a naturalistic substrate can vary based on whether they are meant for an arid or tropical environment but are typically a combination of organic topsoil without fertilizers and pesticides, and play sand. They may also contain other ingredients such as sphagnum moss, peat, or coconut coir to help hold humidity. It is possible for keepers to either create their own substrate or buy pre-made mixes. Before selecting either option, an understanding of what the reptile’s natural habitat is and the humidity levels is important to make sure proper husbandry is maintained. Reptile Ready is a great source for purchasing premixed bioactive substrates for a wide range of reptile and amphibian species. It is crucial to avoid products that contain fertilizers, compost, pesticides, herbicides, and ensure they come from an area free of any contamination.

Exceptions for Using Loose Substrate

Although naturalistic substrates are generally safe for reptiles, sick reptiles and hatchlings can do better on easy to clean substrates such as paper towel, ceramic tile, or newspaper, temporarily. Sick or hatchling reptiles may have more difficulty passing a loose substrate if accidentally ingested, and it is easier to monitor a reptile’s health when they are kept on a substrate where their feces can be easily monitored. Additionally, animals undergoing quarantine should be placed on easy-to-sanitize substrate such as paper towel. Learn more about quarantine procedures here.


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