Category: Uncategorized

When and How to Use Mist and Rain Systems

Misting and Fogging Systems are Often Misused —

There is a place for overhead precipitation systems in herpetoculture – fog, rain or mist – but they are not common. The vast majority of keepers dont need them, and in fact they are very often over used by keepers who have installed them. They should not be a part of a naturalistic or bioactive build unless a species specific needs are being addressed – this is uncommon – or unless they are simply being used to re-wet substrate.

The recipe for bioactive or naturalistic set-ups is typically: Misting system, drainage layer, fancy substrate. But in 95% of bioactive vivariums we can leave all of these elements out. In fact we would do better to leave all of them out.

Misting systems got started when herpetoculturists made the mistaken assumptions that 1.) Tropical species, especially tropical frogs, need very high and constant humidities, and that 2.) the best way to deliver that high, constant humidity was from above via mist. These mistaken assumptions led to the need for special substrates and drainage layers – both needless complexities, and needless expenses and both potentially quite damaging).

For most of our vivariums humidity should come from the substrate. (See: The Humidity Mystery, Managing Substrate Moisture, and Why Drainage Layers Suck). Overhead misting causes quick spikes followed by quick declines – both unnatural and unhelpful. Many keepers resort to closing down ventilation in an effort to keep the humid air around a little longer – compounding one mistake with another.

In fact the entire paradigm of misting system, special substrate, drainage layer is little more than a series of mistakes built on false assumptions about the natural history of the species being kept.

In nature, our frogs, snakes and other species access humidity by going to ground, not by basking in humid air (some exceptions obviously). My dart frogs immediately establish humid refuges under the curls of dried leaves in their vivariums for example. And without any over head mist the humidity in these refuges will remain very high for many days to even weeks if substrate moisture is monitored. (See: Managing Substrate Moisture).

Ball pythons access high humidity by retreating to burrows in the ground during the dry season. Keepers can emulate these natural conditions by using the right substrate (See: Comparing Bioactive Substrates) and learning to monitor the substrate moisture.

That doesnt mean we should never incorporate overhead watering systems. It does mean we should do so only if we are sure the benefits out weigh the costs. And if mismanaged, the cost can be high!

There are two times when mist or rain systems can be useful. One is when you are using them to simply re-wet the substrate. Deep potting mix substrates (See: The Great Substrate Debate) needs to be recharged every week, every couple weeks, or every month or two depending on the substrate depth, cage ventilation, radiation, etc. I have built these re-wetting systems out of 1/2 inch PVC pipe with very small holes drilled into them and then attached via plastic tubing to an inexpensive water pump placed in a 5 gallon bucket filled with warm tap water.

If you have big cages, or lots of cages, its easier to re-wet substrate with a built in system like this than with a hand mister or hauling jugs of water. This simple system can be connected to the residence’s plumbing system too via a garden hose, further simplifying it.

A note of advice about using such a system. When I posted video of one of my re-wetting systems in action I received a number of comments that I was over-watering. The viewers watched as about 5 gallons of water were run thru the system, which looked to them to be much too much. But in fact I ran 15 gallons of water thru the PVC piping in order to re-wet the substrate in this 8×2 foot cage. It is as easy to underwater a substrate as it is to over water! If you are using good potting mix substrate and not, for example top soil (See: What’s Wrong With Top Soil) or a coconut based substrate (See: What Wrong with Coconut Husk Substrate?), the water will spread through the substrate and create a uniformly, slightly damp (never wet) substrate. But if you dig down into the substrate the following day (give it 24 hours to permeate the dry areas) and it has not evenly wet all the substrate to the bottom, you know you need to add more. If the substrate is actually wet, instead of just damp, you know you have over watered. Expect gnats until you get things dried out a bit!

The second situation you will actually want a misting or rain system is if you are designing for a species that is highly adapted to rain. There are very few of these species! These are mostly species that are highly arboreal in nature and descend to the ground only when they have to. These snakes and lizards and frogs drink or replenish water stores from water droplets or water pools collected in bromeliads and similar plants. Some are actually reluctant to drink from standing water, some apparently can’t or dont. See for example, https://reptilesmagazine.com/keeping-the-java-hump-headed-lizard/

An example are the green tree pythons and emerald tree boas that I keep in cages with warm water rain systems and no substrate at all. These species are stimulated to pass waste when it rains. When they dont have access to rain they can become constipated and require a vets intervention. Watching my snakes react to the warm rain makes me believe a rain system is an important aspect of their care. Note too Im saying “rain” not “mist”. The actual rain drops are more natural and seem to elicit a natural response in these animals.

But because it is rain and not mist or fog, the cages have to be plumbed much as a household shower is plumbed. Excess water runs out of the cage thru a drain and carried to the room drain through PVC drain pipe. Each cage may receive 10 or more gallons of water over a 15 to 20 minute rain a few times per week. My system is connected to a timer so the snake’s showers can happen at night when their warm water use doesn’t conflict with the families!

I will soon update these pages with photos and videos of how the rain and re-wetting systems Ive built are designed.

Why Drainage Layers Suck

There is almost never a good reason to use them —

I dont think there is any aspect of modern herpetoculture quite as ridiculous as the drainage layer. Incorporating a drainage layer in a vivarium is akin to keeping a mop and bucket in your bathroom for those times you overflow the bathtub. Here’s an alternative to that bucket and mop: stop overfilling the bathtub.

Its worse than that though. Drainage layers can cause serious harm, even death to vivarium inhabitants. They promote the growth of bacteria and potentially pathogenic viruses. They promote over watering which is a common cause of water related disease in both reptiles and amphibian, and they have not infrequently trapped and killed vivarium inhabitants under the protective screening.

Misting systems can easily compact the substrate and drive air pockets out, which destroys the bioactivity of the substrate and creates an anaerobic environment that is as stinky as it is dangerous. The mistake of drainage systems, caused by the mistake of misting systems, thus leads to the mistake of compacted, dead substrates. And of course all these mistakes result in the development of expensive, but largely worthless “bioactive substrates” that the bioactive companies offer in spades. Oh what tangled webs we weave!

(Not entirely worthless – See: When and How to Use Mist and Rain Systems)

On top of all that bad, they actually go one step worse by doing absolutely no good. Drainage layers got their start, near as I can tell, by keepers who wanted to compensate for another bad vivarium technology – the misting system. Misting systems can be used to the benefit of the kept, but 9 times out of ten they are over used. The misting systems, in turn, were devised in response to yet another misunderstanding in early dart frog keeping: that very high humidities were “natural” and that this high humidity was best delivered from above via misting. (See: The Humidity Mystery).

So once these early keepers got their misting systems all revved up and saw all the wonderful mist raining down on their tiny tropical vivarium inhabitants they couldn’t control themselves. It was just too cool to use only once a week, which would have saved them a lot of grief in the long term! To this day I hear recommendations of misting vivariums daily. Even multiple times per day – creating an artificial environment that can not be found in nature and that no animal is adapted to. (OK, so I can think of a couple misty highlands that actually do look like modern bioactive fog-fests, but very few of our captive species come from these rare environments – certainly the tropical dart frogs do not.)

So if you are not able to control your misting system, you’ll soon have a paludarium instead of the terrarium you intended. The obvious solution, and the more natural solution, would have been to back off on the misting. I’ve tried to describe elsewhere that in nature humidity comes from the earth, (See: The Great Substrate Debate, and Managing Substrate Moisture) not the sky. The unhelpful paradigm of trying to raise humidity by misting is difficult and even detrimental to the animals’ health. It should stop.

And yet it is common for new keepers, even some seasoned keepers, to reflexively recommend drainage layers (and misting systems) as part of a natural or bioactive set up. I have even read recently where someone has made up the idea that drainage layers facilitate a supposedly important “watering from below” of vivarium plants. This fantasy apparently stems from the practice of watering bedding plants, particularly seedling vegetable plants that easily succumb to stem rot, by filling the trays the pots sit in with water and allowing the water to be absorbed from below. While this is indeed helpful getting your vegetable garden started, it has no purpose in hepetoculture.

In summary, I would suggest that we should never incorporate drainage layers unless there is a specific species need that justifies the cost, complexity, and potential down sides of their use.

The Humidity Mystery

Humidity should come from substrate, not misting —

How often have we read of a keeper complaining that they cant get their enclosures to the humidity levels stated on care sheets? Or conversely, a keeper explaining, “I dont know what’s wrong – I have the humidity at the perfect level!”

For keepers with little exposure to reptiles and amphibians in the wild, or to the natural history of their animals, humidity seems to be a setting the keeper tries to achieve in order to be “perfect”. Like setting the thermostat in our houses at 70F – perfect!

We see keepers – some experienced, mostly new – stick a little hygrometer up on the wall of their enclosure where no animal lives and then try to force the humidity up to the care sheet’s recommended levels thru overhead application of water with misting systems or closing off ventilation, or both. Often with disastrous results for the animal.

I recently read a discussion where the “group expert” was explaining to a new ball python keeper that they need to get the cage humidity up to 65%. The new keeper was misting daily and closing down vents to achieve this, while the overhead incandescent was working just as hard to dry the cage down. And of course, the little round hygrometer was stuck up on the side of the cage wall refusing to comply.

This brief exchange teaches a couple important lessons. Without a knowledge of the snake’s natural history, the keeper couldn’t assess the misinformation she was getting from the group expert. And second, its not easy to create high humidity by misting. Light mists of water land on surfaces and quickly evaporate. The result is a brief spike in humidity – not very helpful.

But lets back up. Why would the group expert recommend 65% humidity anyway? Most of the ball / royal pythons we keep as captives come from the Sahel region of Africa, specifically northern Ghana and Togo. The relative humidity in these areas can average 65% for a couple months during the rains, but most of the year it is much lower, and in fact quite arid. (1) And if the animal’s natural history indicates it is adapted to a wide range of humidities, from averages as low as 20% to as high as 65%, why are the experts recommending 65% all the time? What are they missing?

Obviously, the humidity needs of any species changes over time. From hour to hour, day to day and season to season. Aiming for a single “perfect” humidity doesnt make much sense. Using our Python regis as an example, a snake laying in the sun digesting a meal at the entrance to a burrow may be bathed in near infra-red radiation, high UV levels and surrounded by very dry air. It may spend minutes or hours in these conditions, and it may descend into it’s burrow to experience much higher humidity and much lower temperatures. So why are our experts recommending 65% humidity?

Because the keeper doesnt understand the specie’s native environment, and as important, the specie’s behavior within that environment – they can’t interpret the “experts” bad advice.

So now with that in mind we can revisit the question: What sense does it make to try to increase the humidity for a ball python laying out under the warm basking lamp by misting? I hope its obvious now that this strategy is not likely to succeed.

In nature animals know that humidity is found in the ground, or on the ground under cover. Even in tropical areas the animals will experience a range of humidity. One of my first a-ha! moments came while searching for dart frogs (Oophaga) on Isla Popa in Panama. The indigenous guide insisted we could find them but it was hot and sunny, even though it had rained that morning. It was not at all what I imagined dart frog habitat to be like. But of course my guide was right and we discovered a number of them – often sitting in the hot sun! I watched though as they jumped out from under the dried leaves for a moment, then quickly hop back under them, moving from cover to cover while searching for prey, mates or whatever.

Wherever I went in Panama or Costa Rica I found the same thing – the dart frogs often on dry ground, dry forest litter, or up on dry branches and plants. Nowhere did I find the misty, foggy, sopping wet environment I saw in the dart frog hobby – or the tree frog hobby for that matter. Tree frogs were up in dry trees, glass frogs were way up in dry trees, sometimes in sunny, breezy conditions.

I eventually created some vivariums that mimicked the conditions I saw the frogs in in the wild. They worked perfectly. Occasional hand misting and a slightly damp potting mix substrate with a cover of protective leaves provided the frogs with conditions similar to what they would experience in the wild. I thought they were great, but my creations were destroyed by the dart frog community! Many became so angry that they would mount attacks on my social media groups. And of course I was immediately booted from almost all the dart frog discussion groups by the experts who couldn’t bare to witness the travesties I was recommending!

But in both of the examples, the dart frogs and the pythons, we see two important aspects of cage design. One is that humidity comes mostly from below – from the substrate – not so much from the misters above. (Misters are not bad, per se, but they are often used inappropriately. There mere presence of a misting system send many keepers down the wrong path to over watering, and poor humidity management.)

And two, our animals understand that the ground provides the humidity they need. We have to incorporate this understanding when designing cages.

A quick example: A study of cane toads showed that the animals had mental maps of their territory and selectively choose shelters that had the humid conditions they preferred. (2) I have watched my dart frogs, turtles, lizards and snakes do the same. Animals will burrow into substrates or take refuge under surface debris in order to find moisture. Even tree frogs will come down from elevated perches to get under forest litter rather than desiccate in dry conditions aloft.

This is why substrate choice (See: The Great Substrate Debate) and carefully managing the water content of that substrate (See: Managing Substrate Moisture) are two critical aspects of cage design.

1.) https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/met.2049

2.) https://www.jstor.org/stable/3892986

Are Clean-up Crews a Waste?

CUCs are largely a waste of time and money —

I think it will come as something of a shock for some to learn that the whole “Clean-up Crew” thing is largely a figment of our imaginations. The Crew is generally presented as helpful little beasts that busy themselves “cleaning” our vivariums. They do this, as the story goes, by eating up all the animal waste and fungus – removing everything nasty from our vivs and leaving a disease free and healthy environment in their wake.

The truth is isopods and springtails provide nothing that is beneficial to a bioactive or naturalistic vivarium. First, if you have fungus your vivarium is simply too wet. This is true whether you are keeping dart frogs or water dragons or any other species. The simple remedy is to stop watering so much and increase ventilation. If you are watering and closing down ventilation in order to increase humidity then most likely your design is wrong. (See: The Humidity Mystery).

Second, in the experiments Ive done in typical vivarium conditions, springtails simply had no impact on the fungus that I purposely grew. In fact the control container had less fungus growing than the container with the healthy springtail population. So hopefully we can stop with this unnecessary complication to our enclosures.

Its often said that isopods will help decompose animal waste thereby reducing disease and just generally keeping things tidy and clean. I think this idea appeals to keepers who are just uncomfortable with the idea of accumulating “toxic” wastes in their vivarium. But the discomfort is unfounded.

I first started questioning the idea of isopods in vivaria when dealing with our flock of chickens. They would free range all day and return to their coop at night to poop up a storm. And a couple dozen chickens can produce a surprising amount of poop! Their feces fell from their perches to the deep bedding of wood shavings and straw. I read that back in the days that our farm was built the farmers would allow the waste to build up thru the summer and by fall the decomposing waste would actually provide heat to help keep the chickens warm on cold winter nights.

When winter came I turned the foot deep shaving in the coop and found the lower levels had become a rich humus. No smell was present and it was indeed warm – steam rose in a cloud above the overturned substrate. In the spring the coop was cleaned out and loads of rich compost were wheeled down to the garden.

What I was leaning of course is that bacteria are incredible decomposers. This was further established when I was told that local hog farmers are now composting their dead hogs – all 350 pounds of them – in nothing but piles of damp sawdust. Research showed that this simple process depending totally on bacteria would decompose these massive carcasses complete, teeth, bone and all, in a matter of two months under good conditions – conditions that are exactly what we have in our vivariums – warm and slightly moist.

I realized that if bacteria could do all this it could certainly handle our pet’s waste. And my experiments proved it could indeed. In fact side-be-side comparisons showed that the addition of a variety of isopods did not spend the decomposition of animal waste at all – even with a very robust population of the bugs in ideal conditions.

So instead of adding a bunch of bugs that evidence indicated could not help, I tried three different approaches to waste management. I started by filling each of the cages with deep potting mix substrate (See: The Great Substrate Debate). In one cage that housed arboreal snakes I used a one gallon pump sprayer to spray the feces off the plants and cage walls maybe once a week. In a cage housing terrestrial Colubrids I used a big metal spoon to flip the waste over into the potting mix substrate, and in another cage housing a terrestrial snake I didnt do anything at all with the waste.

What I found was that the animal waste didnt last long in any of the experimental cages. Even in the one where I did nothing with the waste, a layer of dead leaves on top of the potting mix substrate trapped the moist air rising from the slightly damp substrate creating a perfect environment for the bacteria to quickly break down the waste.

The arboreal cage too never needed even spot cleaning. The weekly spraying rinsed the waste into the substrate where it was quickly decomposed. I thought about all the times I read about how the big Colubrids I was keeping were supposed to smell so bad. My cages holding these big snakes smelled like the forest after a summer rain.

There have been a couple other aspects of the “Clean Up Crew” that some have touted as essential, or at least beneficial. Some have claimed they keep the substrate aerated by their burrowing. Others have said the bugs are an important supplemental hood source for their animals.

But if you use the right substrate, ie a good quality potting mix, you dont need additional aeration of the substrate. This is simply because potting mix has been designed specifically to allow air to penetrate it, unlike many other pet branded substrates. (See: What wrong with coconut husk substrate?) Since isopods live on or just below the surface, they dont do much aerating anyway. And because you are using the right substrate and learning how not to over water it, you wouldnt need them even if they did. (See: Managing Substrate Moisture)

The idea that the bugs could supplement feeding is worth examining too. I kiddingly liken this argument to new parents planting an apple tree in their backyard in case they forget to feed their children.

Of course if you put bugs in an insectivore’s cage the bugs will get eaten. But then what? You add more? Or you just let them limp along without the important supplemental food source? Obviously if we have pets its our job to make sure they are eating the quantity and quality of food needed to be healthy. If that means adding isopods occasionally then there is nothing wrong with that. Just so its understood the bugs are food, not cleaners.

Finally, if you simply enjoy bugs in your care then there is nothing wrong with keeping them as pets of sorts. As long as they dont bother your primary resident and as long as they are not acting as disease vectors. We dont want to spend time or money on things that dont add to the welfare of the lizard, frog or other herps we are keeping.

What’s Wrong with Coconut Husk Substrate?

These waste products from the coconut industry are not good substrates —

There are a lot of different coconut husk products sold as substrate for our enclosures. These are a waste product of the coconut industry – not specially designed for enclosures. And they fall far short of what our animals need. They are no better than wood shavings, which are terrible substrates.

A good substrate has specific characteristics (See: The Great Substrate Debate) that provide humidity, hold moisture, drain well and allow air to easily penetrate. These are important features for plant growth and for bioactivity too.

The coconut husk provides none of these, or at least none of these very well. When wet it compacts, squeezing out air pockets and inhibiting bioactivity. When dry it turns to dust. It does not support plant growth over time.

Finally, it is expensive, especially for a waste product. My comparisons show that in local stores one example, called Eco-Earth is almost 300% more expensive than the small bags of Miracle-GroPotting Mix. Thats a huge, totally uneccesary cost when you can provide better for less.

Three Big Sources of Herpetoculture Misinformation

These are not the best places to find information about your reptile or amphibian pets —

There are 2 themes that run thru advice I give to beginning reptile and amphibian keepers: One is to look deeply into the animal’s natural history – let nature be your guide. The second is to be very careful about who you listen to when looking for this information.

The first one is easy. The species you are interested in providing a home for has been interacting in an intimate dance with the natural world for a million years. Every nuance of your captive design should be informed by the result of those million years. Not “mimicked”. Thats a mistake keepers often make. But “informed by”, or guided by. More on this later.

The second point is a little more subtle. And is often resisted for a number of reasons. In the 50 years Ive been keeping all manner of herps there has never been such an abundance of information on their captive care. And there has never been such an abundance of nonsense the well intentioned keeper has to wade through.

The three biggest sources of misinformation comes from the 3 sources most often accessed by new keepers: 1.) Pet supply manufacturers and retailers, 2.) Social media “influencers”, 3.) Other keepers and breeders in the hobby.

This point is complicated by the fact that you can get good information from all three of these sources. But much of the time – indeed most of the time – you wont be getting good information from any of them.

Pet manufacturers and retailers online or brick and mortar, exist to sell stuff. Everything they do is designed to fulfill a single goal: increasing profits. And because of this they commit two herpetoculture sins: 1.) Manufacturing unhelpful (and in many cases, downright dangerous) products, and 2.) Employing often uninformed non-experts whose job is to push these products on unsuspecting hobbyists regardless of the negative consequences for the pets involved.

One thing you will never see: A well seasoned herpetoculturist pushing a cart full of reptile supplies thru PetCo. The longer any of us are in the hobby, and the bigger our collections get, the less we shop at pet stores or buy pet branded products. Through many years of experience we have learned that most of what’s sold by the pet industry is either unnecessary, overpriced or even dangerous. More on this later too.

The copious quantity of nonsense the social media influencers produce can be more of a challenge for the new keepers to wade thru. After all, these folks are influencers because they are likable, amusing, friendly and superficially well informed – relative to the beginners they are talking at. But they too have one job: to sell themselves or their products, or their sponsors’ products. Everything they do is done to improve their bottom line. And that means that even though they often present themselves as educators who care about you and your animals, they are often more like used car sales men and women trying to get you in that shiny new convertible no matter what they have to say to do so.

Watch them if you can stand it – (many of them are hard to watch if you have much experience because their self confident ignorance is hard to stomach) – but don’t believe them. They have an agenda: win your trust, then abuse that trust.

And finally the keepers or breeders that work with the animal you are looking to provide for. You would think these folks would be the perfect authority, right? After all, they are successfully keeping the species alive and in many cases reproducing them. Isnt that the best credentials? Well, sometimes yes, sometimes no.

Many breeders prioritize profit over the animals well being. And many are simply not interested in providing high quality care. They may emphasize how “simple” the species is to care for in order to generate sales. Or they may be well intentioned but uninformed.

Simply keeping an animal alive and producing young is actually a very low bar. Animals will survive terrible conditions and will reproduce under terrible conditions. In the livestock industry highly intelligent animals will survive and reproduce in deplorable conditions. Puppy mills will pump out dozens of puppies while living in wire cages stacked to the ceiling in dark barns. Even humans kept in solitary confinement will survive and will not loose their desire to reproduce.

I want to go into more detail on each of these potentially bad sources of information. I also want to better explain the first point – looking to nature for guidance: Earth, wind, sun and water. We cant hope to design quality captive environments without first understanding where to go for good information, and who to listen to with a great deal of skepticism.

Is Miracle-Gro Potting Mix Dangerous?

Miracle-gro is perfectly safe. But misunderstanding fueled by misinformation abounds —

I was so happy with the results I was getting with my “Simple Bioactive” cage designs (See: A Quick Overview of Simple Bioactive) that I completely overlooked the gathering storm of outrage from my fellow keepers! Unknowingly, I offended the closely held dogma of a number of keepers – from dart frog (especially dart frog!), to other frog, snake and lizard keepers. Almost none of the criticism was fact based. In fact so much of it was bordering on the personal and hysterical that I had to learn to reign in my response!

I wouldn’t care at all except I have found Miracle-gro potting mix to solve a number of herpetoculture problems and provide a significant boost in the quality of care we can offer our animals. So I really wanted to share the news. But my “Middle Way” (See: The Middle Way of Herpetoculture) didnt just present a new paradigm, it undermined the authority that group “experts” were enjoying at the time. It was through this process that I realized I was offending a set of dogmatic beliefs as deeply held as any sincere religious beliefs. It was a fascinating experience that brought me back to my days as a graduate student in Anthropology at the University.

The fear that this new paradigm manifested in many produced an endless stream of assertions about the danger of my methods in general, and Miracle-gro potting mix in particular. A few were sincere concerns presented by genuinely curious keepers. Most where defensive, angry, childish and down right silly. I would guess that I have probably been banned by more Facebook administrators than any other serious herpetoculturists because of these insecurities. And that is pretty sad.

So what are the concerns and what can I say to dispel them? Most are concerns about the fertilizer that commercial potting mix contains. Some mention specifically the “synthetic” or man-made fertilizers specifically.

There are concerns about the little white “perlite” things. Some mention pesticides too. Some are concerned about “chemicals” in general.

The easy answers are pesticides and perlite. In the US our Environmental Protection Agency requires any product containing any pesticide to be labeled with the exact contents and amounts. Its a federal offense to ignore this requirement. So we can be assured there are no pesticides to worry about.

Perlite is simply rock. It is inert and can not swell. It is derived from obsidian (a type of volcanic rock) that is ground up then super heated to “op” or “puff” like popcorn. If ingested, which is unlikely, it would pass just as any small rock would.

But what about the chemicals? The first thing to understand is that life on earth depends on the 3 main “nutrients” that plants must have to survive: nitrogen (for plants it would be in the form of nitrate – NO3), potassium and phosphorous. These three chemicals are the fertilizers that our potting mix contains.

When we buy fertilizer we can buy organic or synthetic. Organic fertilizers are derived from bat or bird feces, the waste from slaughter houses or even human sewage. These organic materials are slowly broken down by bacteria into their chemical components, some of which are nitrate, potassium and phosphorous. These are the exact same chemicals that are created thru man-made processes. If they were different in even the smallest way, the plants would not be able to use them. So there is no difference between the chemicals derived from man made processes and the chemicals derived from natural processes.

Imagine for a minute that you were in the hospital with a serious case of Covid. The doctor realizes you’ll need supplemental oxygen to survive. But when the nurse rolls the oxygen tanks in you refuse, stating that the chemical oxygen is man-made and not naturally derived. Sounds silly right? But that is the exact same argument many people try to make against the man-made nutrients found in Miracle-gro potting mix. Equally silly.

The second concern most often stated is that the nitrogen itself is toxic. That exposing our animals to even tiny amount of nitrogen is reckless and cruel. “I don’t intend to poison my animals even a little bit!” is what I have heard.

But this too makes no sense. Nitrogen is critically important to all life. A whopping 78% of the air we breath is nitrogen. Nitrogen is in every natural soil that is sustaining plants. And Miracle-gro potting mix has only tiny amounts anyway – 0.06% nitrogen, and even less potassium and phosphorous. Further, nitrogen moves quickly thru soils and substrates, it is decomposed by bacteria and it is taken up by plants. The tiny amounts of nitrogen in MGPM is literally gone within a few weeks of opening the bag and setting up your vivarium.

I have explained to people that I use a highly concentrated form of nitrogen called urea to feed my sweet corn. Sweet corn, unlike most plants, can handle huge amounts of nitrogen. I buy the urea in granular form and side dress the rows of corn by hand. This product is almost 1000 times as concentrated as the nitrogen in MGPM, yet it doesn’t even cause a rash on my bare hands.

I suspect the misunderstanding and fear of nitrogen comes from the fact that nitrate in aquariums is toxic at high enough concentrations, and that nitrate in drinking water can cause Infant methemoglobinemia (blue baby syndrome) in human infants. Technically, infants have a lower NADH- cytochrome b5 reductase activity (1) which reduces the oxygen carrying efficiency of their hemoglobin.

By the time human babies are 4 months old or so they have developed the gut bacteria needed to safely metabolize nitrates. It is important to note that at this time nitrate are not “a little bit toxic” – they are non-toxic. Just like the salt you put on your French fries is not a little bit toxic, even though salt in sufficient concentration would be lethal.

In aquariums nitrate is potentially lethal to any organism that breath thru gills. (Nitrate itself is not toxic and is even added to heavily planted aquariums as a needed fertilizer. High nitrate levels indicate potentially high nitrate precursors, nitrite and ammonia, both of which actually are toxic (2)) This is something anyone who has ever set up an aquarium understands well. It is not new news. Fish and tadpoles will suffer and eventually die if nitrate levels remain too high. But again this is because the nitrate interferes with the transfer of oxygen to the animal. It is not otherwise toxic.

I recently set up an aquarium I intended for some red-eye tree frog tadpoles and Dendrobates tadpoles. I used a couple inches of fresh MGPM as a substrate, covered with a 1 inch layer of aquarium gravel. All the aquarium occupants did great, eventually metamorphosing into adult frigates right on schedule. A group of fancy guppies kept in the sane tank grew and reproduced as expected. The supposedly “toxic” MGPM provided a great substrate for plant and algae growth – perfect for hungry tadpoles.

In addition to aquariums, I have raised horned frogs in MGPM. They remained burrowed down into the substrate unless they were hungry, when they would climb back to the surface to feed. Ive raised Dendrobates (dart frogs) on it, snakes, turtles, lizards – even isopods and springtails. All did great and remained healthy. I have literally dozens of herps living on and in MGPM and have had them on it for years in many cases.

Finally, when some folks who were most vocal about there misunderstanding were told I had many animals living on the substrate they claimed that the poisonous effects might not appear for years, or may not appear even until future generations were produced! Of course this is an argument that has no evidence, and hints of desperation. We could level the same charges against any product ever created for human or animal consumption. Without evidence these sort of charges cant be taken seriously.

1.) https://en.wikipedia.org/wiki/Blue_baby_syndrome

2.) https://www.tfhmagazine.com/articles/freshwater/keeping-up-with-nitrate

The Great Substrate Debate

Why potting mix is the best option for many reptiles and amphibians —

I want to talk here about why potting mix works so well for so many of our frogs, turtles, lizards and snakes, but I also want to just briefly dispel some of the myths. For a deeper dive into this topic see: Is Miracle-gro Potting Mix Dangerous?

(I use Miracle-gro brand potting mix because of all the varieties Ive tried it provides the most consistent quality. There is no reason to use the “organic” variety unless you simply prefer organic products in general.)

Substrate is one of the 4 key elements of enclosure design – the sun, wind, and water are the others. Substrate is the “earth” for our animals. And as the earth, substrate provides humidity, security, cooler temps, shelter from overhead radiation, exercise and enrichment. It is as important as any of the other 3 key elements of enclosure design, but it is the one most keepers seem to get consistently wrong.

I have found that a good, quality potting mix best meets the needs of many of the species kept. Potting mix is superior to wood shavings, coconut waste products (See: What Wrong with Coconut Husk Substrate?), fancy bioactive substrates (See: Comparing Bioactive Substrates) and any others Ive tried. The only critically important problem it can present is if the moisture content is not managed properly by the keeper. Thankfully, potting mix is more forgiving than the other substrates in this respect. (See: Managing Substrate Moisture)

A substrate should be a humidity sink. (See: The Humidity Mystery) How many times do we hear of a new keeper trying to increase the humidity of their enclosure – often by misting, or closing down ventilation? These are not effective means in most cases. In nature humidity retreats are provided by the earth. Often a layer of forest litter, dried grasses, slabs or bark, flat stones or other surface material creates high humidity refuges that the animals take advantage of when needed. The humidity of the air above the surface really is of secondary importance as long as the humidity layer provided by the substrate is available. (See: Managing Substrate Moisture).

A deep (4-8 inch) substrate of potting mix will be loose enough to allow the animals to burrow through it but will also be firm enough to hold the burrows created. Even species that do not typically burrow will often create depressions under surface cover as retreats. And better than hide boxes, these self made depressions fit the animal snugly, providing the security they need.

The process of creating burrows is perfect exercise for our animals, and provides us with a great opportunity to observe their natural behaviors. Its great to see a hog-nose snake pop up from a vigorous burrowing session with a big dollop of substrate piled on top of it’s head. We know we are doing things right when we see these healthy natural activities.

For some burrowing lizards and species adapted to more arid environments I add up to half course builders sand to the potting mix. (See: Play Sand or Coarse Sand?) The coarse sand drains better and is less likely to compact, so its a better choice for our vivariums.

Species that dont burrow will also benefit from this substrate because of it’s water holding (and releasing) qualities. Dart frogs for example will discover refuges under surface slabs of bark, under low plants or dead leaves that provide high humidity retreats. Understanding how substrate humidity works allows us to avoid the rather silly practice of daily, repeated surface misting in, for example, dart frog enclosures. Research has shown that anurans (frogs and toads) have a mental map of safe retreats in their territory that provide varying levels of humidity. They know where to go to find the environmental parameters they need. (1)

I have watched the same behavior by my dendrobatids. After creating a very simple vivarium for them with deep potting mix substrate and plenty of surface cover, they would explore until they started to identify safe retreats with higher humidity. And just like the various dart frogs I’ve observed in the wild, my captives would move out from these retreats to feed and then return to them as their needs required. With a simple bioactive design like this they could easily go a week or ten days without any sort of misting, just a shallow dish of clean water to re-charge their water balance in.

Finally, lets compare MGPM with the industry standard ABG mix and the bioactive substrates sold by the online retailers (See: Comparing Bioactive Substrates). A typical recipe for ABG (Atlanta Botanical Gardens) mix calls for sphagnum, Tree Fern Fiber, Bark, Peat Moss and charcoal. The bioactive substrates I tested were similar, with the exception of The Biodude’s which was a single ingredient – possibly peat moss.

Miracle-Gro potting mix ingredients are sphagnum, peat, forest products (ground up bark), coir and or compost and perlite. Very similar to the industry standard and very similar to the better substrates sold online, but at a fraction of the cost. The online products also performed rather terribly when I tried to grow plants in them. Because they had none of the fertilizer that the MGPM had, the plants were stunted. Some, like The BioDude’s substrate, didn’t allow the plants to grow at all. The seeds germinated and then the plants literally stopped growing. To remedy this of course The BioDude sells various fertilizers disguised under names like “BioBoost” and BioVibe”. Don’t be fooled.

The key aspect of all these substrates is water balance. The potting mix retains water while allowing for drainage. This brings air into the substrate which is needed for plants and bioactive bacteria. The ABG and similar substrates drain almost completely because they are designed for enclosures that get sprayed or misted repeatedly. As I mentioned earlier, this continual misting is unnatural and detrimental to the animal’s health. Stop over watering and and you will have no need for the expensive designer substrates at all.

1.) https://www.jstor.org/stable/2389843

Whats Wrong with Top Soil?

Many recommend top soil for bioactive vivariums —

Top soil should never be used in a reptile or amphibian enclosure. The reasons for this are two. First, top soil (AKA mineral soil, or “dirt”) compacts quickly and easily. As it compacts it drives the air out of the substrate which destroys the aerobic (oxygen using) bacteria. Without that type of bacteria our substrates go anaerobic, which stinks and stops the decomposition we need for healthy vivariums.

Thats why those who recommend top soil also recommend it be mixed with a number of other materials that makes it less likely to compact. But since top soil does no particular good in a vivarium, why use it in the first place? Bags of top soil are often actually labeled with a warning that the product should not be used in containers – it doesn’t get much clearer than that!

Second, top soil in the US contains whatever pathogens were found in the ground where the soil was dug. That means you can needlessly introduce parasites like mites, ticks or round worms, viruses like snake fungal disease or pathogenic bacteria into your vivarium by adding top soil. (1)

The confusion seems to originate from the fact that “top soil” in Europe can be a very different product than what traditional has been called top soil in the US. It may be sanitized, for example, or contain additives that make it less problematic in a vivarium. And recently there have been products introduced to US markets that are labeled top soil that are probably more similar to some of the European products.

But since “soils” do us no good, we dont need to worry about too many details. If the bag says top soil, or if the ingredients say soil, leave it.

Potting MIX, not soil, is what you are looking for.

1.) https://ag.umass.edu/home-lawn-garden/fact-sheets/bagged-potting-mixes-garden-soils-for-home-gardeners

Gnats and Flies are Your Friends

Where do those freakin’ gnats come from? How can I get rid of them? —

We have Fungus gnats and phorrid flies because we keep our vivariums too wet. The best (and easiest) way to get rid of them is to let our substrates dry down, and stop over watering. Simple, right?

Not quite so simple. Keepers over water their vivariums for a number of reasons – all well intentioned, almost all misguided. So it is probably just as important to understand how and why to stop over wetting our vivariums. The first mistake is installing a drainage layer (See: Why We Dont Need or Want Drainage Layers). The second mistake is over using a misting system, (See: How to Stop Abusing Your Misting System). Adding too much water is probably the single biggest mistake we herpetoculturists make with our vivs. There is a whole bioactive industry out there that encourages this mismanagement. (See: Why We Should Avoid Bioactive Suppliers).

A lot of over watering comes from a misunderstanding of the humidity needs of our animals and how to provide it (See: The Humidity Mystery Unraveled). The current paradigm mistakenly states that the best way to raise humidity is to apply water from above. In fact the best way to provide humidity for most of our animals is from the substrate – from below. Even dart frogs and tree frogs do not need daily misting in a properly designed enclosure. In fact daily misting is detrimental to the captive environment you have created as well as the species you are keeping – and not just because it attracts flies!

There is a lot of bad information floating around social media about fungus gnats and phorid flies. Keepers often seem confused about where they come from and how to get rid of them. Lets address each of those areas …

Both fungus gnats (Orfelia and Bradysia species) and phorid flies (Megaselia scalaris) are attracted to moist, decomposing organic matter – like the vivarium you insist on over watering.

Phorid flies are attracted to decomposing animal matter as well as vegetable matter. They are sometimes called coffin flies because of their attraction to dead things – like dead people in coffins (1) or scuttle flies because they tend to run across surfaces rather than fly. (2)

Fungus gnats are attracted to damp, decomposing organic matter. They lay eggs in places like our kitchen drains and under the rims of our toilets. And once established in those places they are very difficult to get rid of. In our vivariums they lay eggs in wet substrate, on rotting fruit or vegetables or decomposing leaves, moss, etc.

Where Do They Come From?

First, where they DON’T come from is potting mix. We often hear that they are brought into the home in bags of potting mix. But any quality potting mix is heated to 140F through the composting process used to create the product – a temperature that will kill insects and their eggs. If bags of potting mix have flies its because they have tears or holes in them that the flies entered probably while sitting on the retailer’s shelves. Just look over bags to make sure they dont have holes when you buy them. (See: Why Potting Mix is the Perfect Substrate)

But the flies certainly CAN come from the green house. Eggs laid in the pots while at the green house can hatch after we get the plants home and planted in our cages, or just while they are sitting in the window looking pretty. People will often bring a plant home and repot it with a bag of potting mix, then blame the potting mix for the flies when in fact it was the plant that introduced the pests.

They can also come from top soil, or products containing top soil that have not been sanitized. (See: Top Soil Doesnt Belong in Vivariums). By the way, in the US top soil is not sanitized or composted and so can contain all the pathogens we would find in nature: viruses like snake fungal disease, parasites like round worms, or pathogenic bacteria. It also quickly compacts, which drives out air pockets killing off aerobic bacteria that we have to have for bioactivity (3). In short – do not use top soil, or any product with the word “soil” in the name, or with “soil” listed as an ingredient.

And they can just arrive from outside like regular ‘ol house flies from the outside.

The problem is that by the time we see one, there are probably dozens of eggs already laid in the substrate or on rotting food or feces. So the most likely answer to the question “Where are they coming from?” is that they are probably coming from our poorly managed vivariums! This is also why trying to eliminate them by killing the adults is often futile – as long as one escapes the problem will continue (4)

How Can I Get Rid of Fungus Gnats and Phorrid Flies?

First what wont work: mosquito dunks. And yes, I know everyone suggests them. The problem here is that in order to be effective at killing the larvae in the substrate you need to create a “drench”, which soaks the soil and which makes the over all situation much worse. Now we have a saturated soil drenched with a bacteria (Bacillus thuringiensis subspecies israelensis or Bti, aka Gnatrol) that killed the fly larvae but which will take weeks to dry out, attracting flies all the time before it does. This approach is counter productive! (5)

The situation is similar with nematodes (Steinernema feltiae), which can work under some circumstances but which require a moist top layer of substrate, which we do not want in our vivs. Simpler solutions are at hand. (5)

The other thing that wont work is sticky traps, for the reasons mentioned above. They are also very dangerous around our herps. An animal that simply brushes up against a sticky trap is often hopelessly tangled by the time we discover the problem. Sticky traps can help reduce the adult population of flies, but the adult flies are already short lived and will be quickly replaced by the hatching young.

What will work is simple: Dry down your vivarium. If you have already saturated your substrate by over watering or over misting, open your cage doors, mix up the potting mix substrate to bring the lower, wetter strata up to the top. Keep the heat up to encourage evaporation. And then STOP OVERWATERING! Once we dry the substrate down to where it should be the eggs and larvae will die off. Problem solved.

We do not have to keep the substrate dry however. Water evaporating off substrate is important to maintain the humidity levels we may want. So when the substrate is dried down well we water again, and water well. Misting the top layer is not what we are after here. We want to water enough to wet the lower levels of substrate – but just barely. Then let the whole thing dry down again – much the way soil will in nature between soaking rains.

Because potting mix has been carefully designed to encourage water movement through it, the moisture in the lower layers will wick up and be evaporated off the surface. This produces humidity for the captives (See: The Humidity Mystery Unraveled) and allows the surface of the substrate to dry down while the lower levels stay slightly damp. Our friends the flies can only use the top inch of substrate to lay their eggs, so with that drier surface they have no way to reproduce. And that IS simple.

Now all you have to do is make sure you dont leave food (animal or plant) to rot in the cage. Flip waste into the substrate, or rinse it in with a hand mister, or spot clean if flies appear to be using the animal waste to their advantage. With a well designed enclosure you will rarely have to even spot clean – spraying waste into the substrate or flipping it over into the substrate with a scoop spoon will be more than sufficient. You may find you dont even have to do that!

1.) https://nhm.org/stories/coffin-fly

2.) https://extension.psu.edu/phorid-flies

3.) https://ag.umass.edu/home-lawn-garden/fact-sheets/bagged-potting-mixes-garden-soils-for-home-gardeners

4.) https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ENTO/ENTO-433/ENTO-433.pdf

5.) https://ipm.ucanr.edu/PMG/PESTNOTES/pn7448.html