For a few years now, we have been using bio-active soils in lizard and snake cages.

The idea behind bio-active substrates is that you will have an entire eco system in your reptiles’ cage. The benefits from this are awesome. The natural good bacteria, microbes, isopods, substrate mites, and other insects that live in the soil, virtually act as a sanitation crew. Fecal matter can be completely broken down in less than a day. Even uneaten food items get broken down. Some of our cages have had the same substrate for close to 5 years without ever being changed or even spot cleaned. There are no foul oders or even any trace of fecal matter. It works so well that we may turn up a mouse or rat skeleton every once in a while (in the snake cages). The uneaten food items get broken down so fast that they never really have a chance to stink so they go un-noticed…


Creating a bio-active substrate is quite easy. It may involve things you are not used to hearing like, DO NOT BAKE, CLEAN, DISINFECT, OR WASH ANYTHING. Your friends in natural dirt will take care of all that for you.

My first step is to go to a garden shop and get some organic topsoil… I then head to the beach to get some sand. You can also use play sand that can be bought in home and garden shops. The I go to the woods to collect leaf compost, branches, logs, dirt and rotten wood/logs. I prefer to take ones filled with isopods, millipedes, centipedes, and wood lice/substrate mites. Then I go to my yard and scoop up some fallen oak leaves…

So at the bottom of the cage we mix some of the sand, dirt, topsoil, and leaf compost together. On top of that we add the rotten wood with all who inhabit it… Then we put more of the dirt mix on top of that and we then add the leaves. Your substrate ratios will depend on the species you are keeping. For instance, for most of our varanids and leopard geckos we use a 50% sand, 25% compost, and 25% dirt/topsoil mix.

bio-active reptile substrate

We also add dubia roaches to the cages as well as super worm beetles and larva.

There is never any mold growth or build up of harmful parasites, bacteria, or other protozoa. We have actually had samples tested at the University for free and the soil in the cage is naturally clean.

This system has been tested and works equally well in rack systems. We find that changing the substrate in rack systems every 6 months or so works well. We do not remove all of the substrate in rack systems when we change it out. We only remove about 75% of it so we do not have to start the culture from scratch.

bio-active substrate

This system may not be for everyone but those who have used it see the huge benefits in it. We have seen huge differences in behavior. Animals being kept on the bio active substrates seem to behave more naturally. They are more active and are always on the hunt for food. Our leopard geckos housed on the bioactive substrate will dig burrows and forage for super worms, meal worms, and roaches constantly. One of our female leopard geckos laid a pair of eggs out of the nest box that went unnoticed by us and we found a pair of hatchlings running around the cage one day. It took us a minute to figure out how the two hatchlings got in the cage.

Some people will say that there is a huge risk of impaction when using particulate substrates. The fact is NATURAL particulate substrates will only be an issue if your husbandry is inadequate. When reptiles are properly heated, hydrated, and supplemented, there is little to no risk of impaction and the benefits from using bio active substrates far outweigh the minimal risks.


Gregg MaddenVisit Website

Gregg Madden has been keeping and breeding snakes for well over 20 years. He has bred many species ranging from geckos to monitor lizards and garter snakes to gaboon vipers. Gregg is currently focusing on dwarf varanids and Western Hognose snakes of all morphs. He is also the co-designer and co-producer of a very successful incubation tool used world wide by breeders of all levels and zoological parks known as the SIM incubation container.

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