Enriched Humus Substrate: The Why and How
by Chris Brown
The idea of a humus based substrate came to me about five years ago after I had started two mineralized topsoil tanks. At that time, it seemed like the zenith of aquatic horticulture to me, and it would be fair to say I was very pleased with the results at the time. It was very well understood how to make it and why it worked the way it did. The only thing that bothered me about it was the preparation. Making MTS, (mineralized top soil) is an admittedly laborious process but the pay off is well worth it: A cheap, long lasting reserve of plant nutrients.
Sometime after putting MTS into practice, I remember getting ready to start a third MTS tank which meant securing more certified organic topsoil and the other additives to stabilize and enrich it. But, before I could get around to that, I needed to re-pot some houseplants that were starting to get badly root bound and I had procrastinated long enough on that front.
Personally, I have a specific potting soil recipe that I think gets me the best results for my chosen plants and it involves a generous portion of humus. As I was mixing up this new batch of soil, and then later beginning the long, Zen like ritual of re-potting several houseplants, a thought struck me; Humus is essentially as decomposed as anything can get on this planet and is essentially mature compost. The composting process and the way in which humus is created naturally are nearly the same as how topsoil is mineralized. In fact, the end result is identical; Creating a matrix of stable, though still bioavailable, plant nutrients.
But there is one problem with that, humus is only a collection of inorganic acids and ammonium waiting to be reduced into nitrate. Not that nutritious on its own. So I thought to myself, “Well, what else does it need to be nutritious?” The answer to that is a lot. Plants can’t survive on nitrogen and humic acids alone.
Not surprisingly, I shelved the idea when I realized there is a rather substantial cost to enriching humus at the hobbyist level and went about my business using MTS. Sometime later, I finally got around to that third MTS tank and my local hardware store was out of the usual certified organic topsoil that I normally use. I later found what I normally use at a different hardware store and after securing it, began the long process of mineralizing it.
The big day came and went. After set up, the tank developed many problems that just haven’t bothered me for a very long time – let alone since I had been using MTS. There were many different alga blooming at once, ammonia and nitrite would spike unexpectedly, basic water chemistry was unstable when it came to pH, GH and KH, and some plants seem to thrive while other plants just melted away. I had never experienced something so chaotic before.
I did some searching, researching, reading and interviewing and came to accept as reasonable that quality control in the soil business is spotty at best. Sometimes you get a bad batch. Sometimes the organic stuff absorbs a little of the not-organic-at-all fertilizers and pesticides that are being bagged up right next to it. Or, some bags of certified organic soil get a little too back to nature and get some manure or other rich components in them which can play havoc with our tanks. It’s something that happens but infrequently enough to be tolerated well. I can forgive this and move on.
What I did have a problem coming to terms with when I sat back and thought about it, is that I essentially have no control over this process. Even in the post production process of MTS itself, when you think about it. Ultimately, whatever nutrients are in that bag, whether correctly accounted for or not, are what that manufacturer decided I should get at the moment that particular lot was bagged up and sent to various wholesalers and distributors. It was time to revisit my enriched humus idea, cost be damned.
Having an idea of what humus was missing was easy. It lacked everything but nitrogen. That is easy enough to fix with various amendments and supplements, but how in the world would it perform submerged in water for long periods of time? The answer to that was unexpected.
It is quite abundant in aquatic environments, both in the earth that makes up any lake bottom, or the shores of a river. Two products of humus, fulvates and humates, are found very frequently in the water columns of fresh, brackish and marine environments. What they do exactly is still hard to say but they do seem to have some influence over redox potential and both chemical and biological oxygen demand. They definitely affect KH and pH, lowering both. In fact, it is the presence of humates and fulvates that are chiefly responsible for blackwater conditions. Tannins, which are similar, don’t play as much of a major role in those conditions as previously thought. This information is not new, though many aquarists may find the statement controversial. But when we take a moment to cast off our cherished biases and think critically, it makes sense.
If an area is flooded regularly, like around the Amazon, how do those blackwater conditions occur every Spring if it weren’t for the tannins? That tint to the water is there because of fulvates and humates mostly from the now inundated earth. Humus readily yields up those acids to stain, soften and acidify water. Please note it has almost no meaningful effect on GH.
I came across this information searching for terms like “aquatic humus” and a treasure trove of information bubbled up immediately. The best source I ran into is and will continue to be “Wetland Soils: Genesis, Hydrology, Landscapes, and Classification” edited by J. L. Richardson and M. J. Vepraskas, 2001 CRC Press LLC, ISBN# 1-56670-484-7. I strongly recommend it and it is definitely worth the $120 some odd price tag if you really want to understand wetland soil ecosystems and how they very strongly relate to our glass boxes full of water and weeds. Couple it with Diana Walstad’s “Ecology of the Planted Aquarium” and you have a recipe for very nearly complete enlightenment on the subject.
Naturally, reading this important and dare I say seminal tome only lead to other questions, like, “How are we already doing something like this either intentionally or unintentionally?” and “Should it be fully replicated?” and especially, “What actual analogues already exist in it in the hobby either homebrewed or offered commercially?” The answers to those questions were clear when I stopped to think and ask questions. The best thoughts and answers came like parables from an extraordinary individual whom many may know already. An irascible Socratic by the name of Nikolay Kraltchev or more commonly known as Niko to the hobby.
For years Niko had used the Socratic method to help folks think a little better on the subject of husbanding aquatic plants and animals. Leading discussions that questioned what we think of as cannon, and thus casting out dogma and advancing the hobby scientifically. Niko is what I call a gentle revolutionary.
One of his favorite exercises would be to offer up a beautiful picture of some aquatic scape taken directly from nature with crystal clear waters and lush plant growth, both emergent and submerged. He’d ask how this was possible, while we tend to struggle in the hobby with algae, boom and bust cycles of growth and unstable water parameters. Paraphrasing Niko, “How is it that nature does this so effortlessly, while our tanks constantly teeter on the brink of eutrophic pollution (like EI) or apocalyptic famine (like PPS/Sears & Conlin)?” Needless to say, there is no need to read between the lines with Niko, though his points can be very subtle indeed.
After much exploration, the discourse would indicate that the plants are all rooted in the earth where all the nutrients are, even taking some of their carbon from it (a very tiny amount) and quickly stripping what little enters the water column from run off and decomposition. Staring us in the face was the idea of a lean if not completely depleted water column and absolutely everything our plants need in the substrate and leaving it at that until such time as the tank substrate depletes, which they all do eventually without some kind of intervention. From here, it was a quick hop, skip and a jump to planning and execution, but I was still bothered by the question of whether there was an existing modality for this in the hobby. The answer should have been obvious. Amano Takashi and his ADA line were it, despite what you may feel about him and his practice.
In Theory and Practice
Niko’s line of questioning helped me realized the point of what is Amano-san’s component substrate system, and why there was the appearance of dosing only the minimums. He seems to use lower than usual light, the fertilizing regime seems very light, but the substrate system is very rich though it exhausts itself at a slow rate. The reason for all of it is to create a balanced, whole ecological system that is recharged through water column dosing.
How is his system put together? You have a thin, nutrient rich layer seeded with soil microbes, the Bacter and Penac additives that contain some soil particulates, then a large area of exchange with voids that invites rooting, cation exchange/adsorption and oxygenation known as Power Sand. And finally, you top it with Aqua Soil which is another layer that contains nutrients, can do cation exchange and conditions the water. The idea being to invite natural ecological cycles like the iron and sulfur cycles, aerobic and some anaerobic cycles to create a truly whole integrated system that grows plants indefinitely as long as certain basic inputs are met.
It does exhaust itself, and if you follow his documentation you’ll notice that you are advised not to begin dosing the water column immediately but to wait until it reaches a certain age when you begin more or less adding what is being removed on a regular basis. This is how it works. This is the best practice. But what if you want to go a step further? What if your curiosity and the desire to tinker gets the better of you? What if your requirements demand a degree of granularity beyond what ADA can offer you? That’s what I want to talk about.
With the help of various resources, I found some original high level work that essentially deconstructed ADA Aqua Soil by a group of Russian hobbyists and compared it to other substrates. I don’t know their names and sadly, their work is only on Google Cache these days and it needs to be translated. Google Translate came through for the most part and the authors were amazing in giving us their references. Please bookmark and read the translations of http://webcache.googleusercontent.com/search?q=cache:http://amania.110mb.com/Chapters/Tech/sub-aquasoil.html and http://webcache.googleusercontent.com/search?q=cache:http://amania.110mb.com/Chapters/Tech/sub-profile.html.
To summarize their findings, the base layer and Power Sand layer are well know in the gardening world, these correspond to separate layers of manure, mulch, charcoal and limestone and have been used for a long time as a means of keeping the soil in raised beds aerated as well as a store for nutrients. Simple enough and it makes sense.
The Aqua Soil itself is key. It is essentially a soft clay with humus and other nutrients baked into it and a touch of iron hydroxide which not only softens water but makes the transport of phosphorous more efficient while keeping it sequestered in the soil instead of the water column. Bingo!
Exploding the Enigma
Eventually I began experimenting, that was between two and three years ago. I did so with different recipes and in pots of arguably robust plants namely Barclaya longifolia, Cryptocoryne cordata, Hygrophila corymbosa and Poaceae sp. ‘Purple Bamboo’. Their vessels were solid clay pots that were layered from bottom to top with a humus mixture, a fluffy layer of either carbon, sphagnum moss or lava rock and finally a cap of some inert, high CEC clay like Seachem Flourite, Eco Complete, Turface or Arcillite. The results were good, growth was strong and measured, and the plants could handle low tech and high tech conditions with no transitional issues. Light level even seemed to not matter as long as their basic needs were met and there was adequate flow in the tank. The growth of the Hygrophila and Barclaya was especially aggressive.
This is the point, last year namely, where I began to publicly solicit feedback and finalized today’s production recipe with the help of the community. My home forum, Aquatic Plant Enthusiasts at http://www.aquaticplantenthusiasts.com has been especially helpful and supportive of me. This is the point where I would like to take you on a journey and explain the rest in the form of a time line so everyone can appreciate its evolution without being too long winded. I want the work to speak for itself.
To date, it is still highly experimental and should be approached with caution and no expectations. It also needs to be carefully budgeted for, as it is not cheap to start, but nor does that aspect trouble me. The recipe and practices around it continue to evolve and what you see now may be obsolete in the future. A full pictorial guide of the recipe itself can be found at http://www.aquaticplantenthusiasts.com/substrate/4256-new-recipe-procedure-mineralized-topsoil-27.html#post31443.
A Journey Through Time and Space
This is the initial post on APC where I took what I knew at that time and offered up my work and some conjectures to entice participation. This also illustrates what methods and additives I was working with in September of last year. The additive Azomite is first suggested as a way of introducing various micronutrients in abundance. Here the theme of using certified organic fertilizers just barely begins to germinate.
Here is where the first additives are suggested and I must offer my first justifications and the thoughts on the early components.
Version one of the production recipe suddenly appears from the primordial depths. My early experiments had already been terminated for a few months prior to this.
In as little as four hours a new mutation appears in the wild.
A day later and new selective pressures have spawned another change in ratios.
A week later, 17/09/11 and the first inkling of the quality of the materials appears. Namely, the humus itself.
25/09/11 and the first major revision happens when I realize how calcium and magnesium poor the mix is and in the same breath as I try to fix that oversight, the recipe changes twice and muriate of potash is abandoned and the first organic additive takes hold, Sul-Po-Mag. A mineral that is a rich source of sulfur, magnesium and potassium.
26/09/11 I respond to Niko and the first argument about the need for a dolomitic substance briefly flares up and sputters out. The idea of aragonite as an additive appears.
9th October, 2011 I unleash the idea on my home forum, APE. Interest and discussion is immediate.
After a brief hiatus, on 6th November, I make a major restatement of the project and offer up some sources for some of the materials.
Eleven minutes later, humates are introduced and we become aware of OMRI or the Organic Materials Review Institute. Cross pollination between APE and APC occurs.
A substitute for Sul-Po-Mag is named.
A reformulation is made with viable substitutes named.
On 23/11/11 I believe I have found the final production recipe. This was of course not the end. Ideas from APE start to show up more and more on APC. For completeness sake, I will finish the APC time line. It is unfortunately short and the bulk of development began continuing on APE with a bigger head of steam.
People are now directed to APE.
This leg of the thread begins a small controversy about the nature of wetland soils, misunderstandings of my goals and remediating the shortcomings of natural wetland soils for our purposes. An in depth discussion of various elemental cycles begins.
Ideological contentions appear briefly and are civilly resolved.
And now the APE highlights where the bulk of the progress was made with the help of the community.
The first major restatement regarding the ingredients themselves and a justification for it.
The first blurb about the natural ratios of certain nutrients to each other and why some of the choices I suggest tend to fit into that when mixed together.
The user Madness make some major contributions by identifying some holes and offering great substitutions for some of the ingredients.
A distillation of Madness’ thoughts.
Two new reformulations occur within the same fortnight in early November based on discussions and the help of Madness.
The suggestion of red clay instead of laterite appears. A highly viable substitute. The first volunteers begin to appear.
Volunteer Zero, a fellow by the name of Joe tries an early production recipe and photographs the early components for us on 13/12/11.
In the middle of the thread, Joe begins a journal. This is encouraged and we all hold our collective breath.
Joe starts production and begins planting on 17/12/11 and documents it beautifully.
Joe starts taking regular readings for us. It looks good so far and Joe is enjoying himself.
More photographs from Joe, he does a water change the next day. This is only 18/12/11.
The name enriched humus substrate or EHS takes hold.
Joe experiences a lot of good growth only a few days in.
Joe starts to become a bit of a phenomenon by 21/12/12. We are all rooting for him. His cycle seems to complete very early on.
Joe’s first several days charted out with particular attention paid to water chemistry.
Joe has fully cycled in only sixteen days.
Finally, on 11th January, 2012 a major upsets happens when I make a massive change to the production recipe. Glauconite and soft rock phosphorous are added to the final production recipe to address deficiencies of potassium and phosphorous.
The final production recipe done volumetrically. This is what is in use today.
A friendly, pictorial guide is produced demonstrating the recipe on 22/01/12.
I fully divulge a list of suppliers. It turns out none of it is as rare as we thought it was but quality seems to be all over the place with regards to the humus itself. The best I’ve worked with so far is Ancient Forest brand from Alaska. The only reasonable source I’ve found is at http://www.repotme.com/orchid-potting-media/Ancient-Forest-Humus.html. It contains enough ammonium to do a fishless cycle without giving the plants a bad fertilizer burn.
Jerry the Planter appears and immediately comes up with all manner of helpful substitutes and immediately offers up his expertise.
A case study is begun by Plant Keeper comparing MTS and EHS but must be abandoned when something contaminates both tanks making them toxic. This still remains a mystery. By this point, Joe hasn’t updated any either. We are all troubled by this.
I finally begin my own journal which is still going strong with lots of readings, photos, notes and argumentation. A recent video of the tank can be seen here, http://vimeo.com/37044642.
Thoughts So Far
This substrate system is not kind to plants who don’t have roots, like newly acquired cuttings, or plants that root too slowly after being cut. Only plants with roots or who are capable of rooting quickly will realize the full benefit of it.
Flow and high amounts of dissolved oxygen appear to be crucial to this set-up if you expect the filter bacteria to thrive in such a soft acidifying environment.
The system does leak a little into the water column. It can send the GH rather high until it fully settles, which happened for me after 36 days and seemed to coincide with the completion of the cycle and the addition of fish.
You need to be comfortable with deeply tea stained water.
Phosphorous tests are about as useful as iron tests which is to say not at all.
There was some green spot algae early on but once it hit its stride, it receded quickly along with some red algae. A short eight hour photoperiod also helps a lot. Otherwise, the water column has virtually nothing in it and all sustenance is coming from the substrate itself. I predict a useful lifespan between one year and eighteen months. We shall see.
I am still trying to wrap my head around the appearance of some physiological leaf rolling I’m seeing. I’m thinking it is because of the very powerful light I have available, the only practical solution for the ten gallon test tank is an old power compact fixture with eighty Watts of 6,700° K lighting.
Overall, I believe there is something here. There is still a lot of testing to be done and the proper gathering of empirical evidence and there will come a point where regression testing will need to be done. I’m already seeing that not a lot of plants take to it readily but the ones that do, especially creeping stems and rosettes take to it almost immediately.
I would encourage as many people as possible to try experimenting with it and contribute to it with their time and resources because I think it will be a paradigm shift in keeping with the concepts of balance, elegance and robustness.
EHS will become strong evolving from a community of passionate hobbyists, rather than a committee of a few or from a single authoritative source. A Darwinian approach will help it succeed and ultimately provide a new way for us to forge ahead more rationally and consistently and create something that belongs to all of us; A few basic principles that operate soundly that are consistently reproducible but still customizable to the individual aquarist’s needs.