The choice of your incubation substrate is an important one and which is
best is a hotly debated topic. The most commonly used types are:
- Hatch Rite™
These consist of peat, moss, coconut fibre, soil and other similar media.
The problem with these is that they all hold copious amounts of water near the surface which keeps
the eggs "wet". This can lead to all sorts of problems like mould and bacteria growth. Also
sterilising it is very difficult necessitating purchasing more of it every time. It doesn't tend to
come pre-sterilised either for most of the types and thus bad moulds and bacteria and parasites
could already be in it which will thrive in the incubator environment.
They have their uses but for me - not for
Vermiculite is a natural mineral that expands with the
application of heat. The expansion process is called exfoliation and it is
routinely accomplished in purpose-designed commercial furnaces. It is a limited
expansion clay with a medium shrink-swell capacity.
It has been used for absolutely ages in the reptile industry
but it requires strict moisture management to get the benefits from it. It tends to
get clumpy and sticky when wet - hold moisture well but at the core of the
substrate will tend to clump together and not release moisture efficiently as a
vapour near the surface. The surface area tends to dry out more than the rest over
the duration of incubation but it does have good wicking properties. Moisture
content of the substrate has to be carefully monitored with a suitable regimen and
weighing scales to ensure that the environment doesn't dry out too much.
Sterilising it after use is extremely hard to achieve - but it's so cheap that
replacement is the best option. It is fairly sterile when you receive it in the
pack. It goes slightly darker when wet but colour change is not a great indicator
of moisture content.
I used it myself for over a year but like I've mentioned already it does
require a strict maintenance regimen to get the best from it. It would dry out too fast on occasion
until I got the hang of using it. Recommended but there are better
Perlite is an amorphous volcanic glass that has a
relatively high water content, typically formed by the hydration of obsidian. It
occurs naturally and has the unusual property of greatly expanding when heated
sufficiently. It is an industrial mineral and a commercial product useful for its
light weight after processing. This commercial heating expansion process leaves it
with a great surface area and akin to a hardened sponge. It has the ability to
absorb a great amount of moisture as a result.
For incubation it gained lots of popularity over the last
10-15 years and is probably now the most used medium for incubation worldwide. It
doesn't wick which is a good thing but releases it's moisture gradually over time
as the result of warming - which is what we are after. It resists
condensation occurring, because it is effective in holding it's moisture in
it's cells - thus its great for guarding against mould growth. A good ratio of
Perlite to water is 10:8.
The single drawback to this otherwise ideal
substrate is the fact that it's white when wet
and dry and very difficult to tell when it has lost an
unacceptable amount of moisture during incubation. It needs efficient regular
monitoring and weighing to ensure that it doesn't dry out too much. Many breeders
compensate against this by not having any ventilation holes at all in the Perlite
egg container. Opening the container once a week for oxygen exchange. Another
peculiar problem with Perlite is that when it dries out enough to cause dessication
of the eggs it tends to make the eggs collapse on the underside - meaning you have
no visual clues as to the eggs health until you pick it up - which as you know is
Another disadvantage is that it is fragile - it will
eventually break down into a powder if handled regularly - I liken it to coral in
that respect. It can be sterilised but it's difficult as it floats so boiling
is out. It's cheap enough though that replacement is the best solution.
This is a relatively new player in the substrate field. It
doesn't reveal it's ingredients on the packet but breeders suspect it contains
Perlite and some form of water retaining gel. It comes ready watered for immediate
use in a sealed bag.
It's only drawback is that you cannot gauge how much water
is in the product to start with. It's a good product and ideal for the infrequent
breeder - Not much more expensive than Vermiculite or Perlite.
Difficult to get hold of in
This is a fairly new product from Alan
Repashy in the USA. It's made from Arcillite. Arcillite
is a calcined form of Montmorillonite a substance that is
common throughout the world and goes by other names. Calcination
(also referred to as calcining) is a thermal treatment process applied to
ores and other solid materials in order to bring about a thermal decomposition,
phase transition, or removal of a volatile elements. For example some people
believe that Superhatch is crushed up clay pots that are then re-fired at approx
1200ºC to remove unwanted constituents.
It is a very common component for Bonsai tree growers
because of its excellent water retaining properties. It's that good at it NASA use
it for their plant growing experiments in space. The pores are very small compared
to the other media and this helps lock in the moisture and release it much more
gradually. It's other great advantage is that it changes colour to a dark brown
from it's very light tan colour so is a great indicator of moisture content. When
wetted at first it's ratio of weight to water weight is approx. 1:1. it's hard and
tough - doesn't break down and being heavy can be boiled for reuse. Unlike
hatchrite™ it doesn't contain any artificial water retaining gel.
Sadly - this seemingly perfect incubation medium is Very
hard to get hold of in the UK.
I wanted to try Superhatch but could not find a supplier anywhere in
the UK. It seemed to me to be just what I was looking for in an incubation medium. So I did a bit
of research. Now, Bonsai growers are fanatics - just like we are about our Geckos! So I looked
there first. Do these guys use alternatives to Arcillite themselves??
Arcillite is used as an alternative to akadama in the bonsai world but both
are expensive so do these guys use anything else that they have discovered has the same
properties?? Turns out they do indeed!
Again, these products are all (basically) clay granules that
have been fired/heated to create small pellets or granules that are water retentive, extremely well
draining and are stable, that is they will not breakdown readily. These guys use something called
diatomaceous earth/diatomite as an low cost alternative. So what is
Diatomaceous earth consists of fossilized remains of
diatoms, a type of hard-shelled algae. It is used as a filtration aid, as a mild
abrasive, as a mechanical insecticide, as an absorbent for liquids, as cat litter, as an activator
in blood clotting studies, and as a component of dynamite. As it is also heat-resistant, it can be
used as a thermal insulator. Diatomite is also used as an insecticide, due to its physico-sorptive
properties. The fine powder when dry absorbs lipids from the waxy outer layer of insects'
exoskeletons, causing them to dehydrate. Bonsai enthusiasts use it as a soil additive, or pot a
bonsai tree in 100% Diatomaceous earth. Like Perlite, vermiculite, and expanded clay, it retains
water and nutrients while draining fast and freely allowing high oxygen circulation within the
So basically it has exactly the same properties as Arcillite when in a
calcined form, which is how it's commonly provided.
I wanted to try some of this so where could I get this calcined clay from?
You'll never guess ---
That's right - Tesco's Cat litter - Tesco's Premium Lightweight
cat litter is a 'Moler Clay' and originates from Denmark, exported by a Scandinavian company -
Damolin. Moler Clay is a type of Diatomaceous Earth or 'Diatomite'.
By the way another brand of cat litter that has exactly the
same properties is Pets at Home's Sophisticat cat litter - it's exactly the same
So how do I use this
Firstly I thoroughly wash a batch of it in a sieve in the
kitchen sink to get all the dusty residue off of it. I do this until the water runs almost
clear. I then leave it to drip dry for about 10-15 minutes. My experiments
showed that it absorbed an equal amount in weight of water after this process -- a ratio of
1:1. If you require a smaller amount of moisture then let it dry out a bit first and then spray
water back onto it until the correct ratio is acquired.
I then get hold of a cricket feeder tub. I leave the micro
slits in the side and create 4 more 1-2mm small holes in the lid. Because this stuff absorbs so
much water initially I noticed that it was almost too water retentive - so I wanted to create the
perfect humidity requirements for the eggs by allowing the moisture to escape naturally through the
honeycomb structure and out of the lid. Because the vent holes are literally so small what I get as
a result is a constant stream of humidity on the eggs as the vapour passes them from the substrate
and gradually out of the holes and slits. The moisture is released very slowly by this stuff.
As the outer window of the Herp incubator is exposed to the home environment the inner part of it
does suffer condensation - but most importantly the containers and the eggs do not suffer
any condensation at all - they just have excellent level of humidity 24/7. When
measured it was 80% which is practically spot on!
Maintaining the water content is even easier -I simply
weigh the total amount of the container, litter and water; and mark it on the container with a
permanent marker. I do not monitor it for the first 2 weeks. Every week thereafter I weigh the
whole lot and if it's dropped 5 grams I add 5 grams of water via a syringe near the edges. Handily
1 ml of water weighs approximately one gram - so 5 grams is 5ml
from a syringe - simple as that.
Once a week I open the incubator - open all the lids and allow
some fresh oxygen exchange - this also allows the stagnant moisture vapours to expel a bit. -
The water goes stagnant in ANY medium you use. That's all I do - so far this year
- 100 percent hatch rate with nice 4-5 gram hatchlings in perfect health.
Each cricket tub holds four eggs. When the fourth egg hatches I
throw away the medium into the kitchen bin and then wash out the cricket tub for the next batch.
This stuff is so cheap there is no need for sterilisation to re-use!
This has been my secret medium for over a year - well I
wanted to test it first! And now I'm releasing it to you the public. I "think" I'm the first to
stumble upon this alternative to Superhatch - but saying that I know I have doomed myself to being
told that I was not! If it turns out I am - then give me some credit people! Nevertheless - enjoy