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
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
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
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.
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.
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 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.