The Soil Substrate or Dirted Planted Tank - A How to Guide

Tim Harrison

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The Soil Substrate Planted Tank - a How to Guide...

...or Zen and an Introduction to the Art of Underwater Gardening with Soil or Dirt...
...or The Hybrid-Energy Approach.

Introduction
In writing this I hope to illustrate that using soil substrate offers a range of possibilities and that it's up to the individual to decide on the level of energy investment they are happiest with in order to achieve their goals. I also hope to illustrate that the “hybrid-energy” approach provides an alternative to the traditional low-energy, low-tech soil substrate tank and the typical high-energy, high-tech CO2 injected tank.

But first let’s just put all that high-energy, low-energy gubbins in to context. Aquariums require our intervention to reach a healthy equilibrium. The greater the intervention the greater their inherent instability and the greater the investment in energy required to maintain them (for energy also read effort on your part). For instance, the CO2 route requires a relatively high energy investment not just in terms of adding CO2, but also nutrients, artificial substrates, powerful filtration and high output lighting etc. The soil substrate route on the other hand requires none of these and is therefore considered a relatively low-energy investment with minimal inputs required to achieve equilibrium. However, although using soil substrate in an aquarium is traditionally considered a relatively low-energy approach, it does not necessarily have to be the case; neither does it have to be low-tech.

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Walstad Nature Scape. Scape by Tim Harrison.

Hybrid-energy
The hybrid-energy method uses soil but it can also take full advantage of CO2 injection, LED lighting, powerful filtration, inorganic nutrients, and frequent water changes. And any one or all parameters can be altered according to the desired outcome and the amount of time, money, and effort the aquarist is willing to invest. But before I go on to describe the hybrid-energy methodology in greater detail I thought it would be helpful to define some of the key terms.

What is a soil substrate?
Put simply, a soil substrate consists of mineral particles, organic matter, precipitated inorganic matter and microorganisms. A far simpler definition is ‘the stuff in which plants grow’. This definition emphasizes the biological importance of soil, and I think it is this fundamental importance that is so often overlooked by many aquarists.

Soil substrates use potential energy already harnessed by nature and once your aquarium is full of water it takes advantage of life’s natural flows and cycles. Get it right and soil substrate tanks can produce stunning results on a par with their relatively higher energy counterparts, but with minimum effort and very little expenditure; although it takes a little while longer.

Potting compost
So much of using soil substrates is experimental, and for me that has always been part of the attraction. For instance, I have experimented with several soil substrate formulas in the past, with the aim of providing a nutrient level just high enough to aid good plant growth but low enough to prevent excessive release of nitrogenous compounds such as ammonium. One such formula that has proven successful is a blend of 20% loam, 10% grit and 70% sphagnum moss peat. In simple terms the loam peat mix holds nutrients that plants can utilize, and the grit just adds extra structure so the substrate is more conducive to root development, water movement, nutrient transference, and gas exchange.

But equally you could use aquatic compost, the type readily available at garden centers for use in ponds. Other people have had success using John Innes number 3, or Miracle Gro’s Organic Choice Potting Mix. I have also had great success in the past using sphagnum moss peat on its own or mixed 1:1 with aquatic compost. However, a word of caution, local water chemistry can also play a role too; for instance peat can sometimes drastically reduce aquarium pH in soft water areas which in turn can lead to metal toxicity. But this can easily be remedied by adding a source of carbonate or bicarbonate such as powdered Dolomite to buffer the pH. By the same measure the lime in John Innes number 3 can raise pH and water hardness. But the resultant water chemistry issues aren’t normally a problem unless you’re a specialist and intend to keep or breed species with exacting environmental requirements.

One other word of caution, avoid composts that have added inorganic fertilizers since they can prove toxic to fish and invertebrates. Also, avoid composts containing additives like perlite since it has an annoying tendency to rise to the surface every time the substrate is disturbed.

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My preferred mix 1:1, Credit Tim Harrison.

Garden soil
Garden soil has also been used with great success, however not all garden soils are created equal. Soils behave differently when they are submerged and usually this just means that sometimes they don’t work very well as an aquatic planting substrate; even though they work perfectly well in your garden. In many cases it is the least toxic soil which provides the best growing conditions. Garden soils can also contain traces of insecticide and herbicide and other substances that may prove harmful to aquatic life.

Soil vs potting compost
The advantage of using proprietary brands like John Innes is that they are guaranteed to be of consistent composition, and have been tried and tested and proven to be safe and work well as submerged substrates. This, in no small measure, is also due to their relatively high CEC (cation exchange capacity), which means that they have the ability to absorb and hold nutrients in a form plants can easily utilize.

Lighting
Of at least equal importance to the substrate is lighting, considerations are type, intensity and duration. In a traditional soil substrate tank the rate of photosynthesis is limited by the lack of CO2, so if that’s the route you intend to take there is no need to invest in relatively intense lighting. As a general rule 1 to 2 watts per gallon is perfectly adequate depending on the type of aquarium lighting you plan to use. For instance, if you are going to use T5 bulbs around 1 watt per gallon is a good place to start. I use T8 lighting, about 1.5 watts per gallon, which is perfectly adequate. LEDs are an increasingly popular choice and dimmable units will provide the greatest flexibility.

Lighting duration depends largely on which source and intensity of aquarium lighting you chose. There are no hard and fast rules and a bit of experimentation is needed to get the optimum combination. This is important since in a soil substrate tank, without CO2 injection and nutrient dosing, lighting is usually the only parameter that you can vary to achieve a balanced system; but around 6 - 8 hours is the often quoted standard. In a newly set up tank it’s best to start with a photoperiod of just 6 hours to avoid algal outbreaks. Once the plants are grown in, and the tank becomes biologically stable, the photoperiod can be gradually increased if necessary.

Spectrum (quality of light) is also important to the health of aquatic plants not just in terms of growth rate but in terms of plant morphology, reducing the impact of resource limitation, and triggering life-cycle processes. Therefore, to ensure plants get the quality of light they require most aquatic plant growers tend to use full spectrum bulbs with a colour temperature of around 6500 kelvin. Luckily we also find them aesthetically pleasing. It's a function of the fact that the photosynthetically active spectrum and the visual spectrum are one and the same give or take a few nm; which is a happy coincidence of evolution.

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Soil Substrate CO2 Tank: Lighting. Scape by Tim Harrison.

Siesta Period
A siesta period is something of a contentious issue. Put simply it involves turning your tank light off for 2 to 4 hours in the middle of the photoperiod to stop photosynthesis and allow CO2 levels to replenish. The theory is that your plants then take advantage of the higher CO2 levels when the light is switched on again, increasing photosynthesis and growth. This in turn could help plants maintain dominance over algae.

Filtration
Get the balance right between bioload and plant density and you can do without a filter completely. Plants are very efficient water purifiers and readily uptake the toxic waste products excreted by fish and shrimp, such as ammonium, and use it as a source of nutrients. I choose to use filtration because it allows me to safely increase the bioload, to something approaching tank capacity, it also comes in very handy should I inadvertently disturb the substrate whilst moving plants around.

Water Changes
The same goes for water changes. Even if you chose to stock to capacity like I do, water changes will not be required anywhere near as frequently as say a CO2 tank using a eutrophic nutrient dosing method such as EI (Estimative Index); about 20% - 30% every other week or so should be fine in most cases. But it also depends on the species of fish you decide to keep and their feeding habits; some are not particularly well suited to lower energy tanks.

However, I choose to change about 50% of the aquarium water once a week and use it as an opportunity to reduce the concentration of both dissolved and solid organic compounds in my aquarium. This may rob plants of a potential source of nutrients, but I prefer to dose with inorganic nutrients anyway and a very clean tank appeals to my sense of aesthetics, and it may also help to prevent algae. In a newly set up tank even more frequent water changes are often recommended, but it's usually not that essential in a low-energy setup. Nevertheless, I usually change about 50%, 2 or 3 times a week for the first 2 weeks. Again this is to reduce the concentration of organic nutrients, but in this instance those that are excessively released by newly submerged soil, which in turn may help to reduce the likelihood of an algal outbreak.

Water flow
Good circulation is essential to disperse waste products and to ensure that all plant leaves are bathed in a homogenous solution of nutrients and dissolved gasses. This will help to promote better growth and prevent algae. Good water flow also helps to drive nutrients in to the substrate where they will become available to plant roots. However, if the circulation is too vigorous your plants will have to invest more energy in repairing subsequent mechanical damage rather than in increasing biomass or growth. Water flow just adequate enough to produce a gentle swaying motion in most of the plants is considered optimum.

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Soil Substrate CO2 Tank: Flow. Scape by Tim Harrison

Surface Agitation
Good surface agitation ensures adequate oxygenation, essential to maintain the health of critters. It also inhibits the formation of surface biofilms, which not only restrict surface water gas exchange but look unsightly. Don’t forget plants also need oxygen, as do some beneficial microorganisms especially those that break down organic matter. In a soil substrate tank this in turn can lead to the production of more CO2. In many freshwater bodies this decomposition produces far higher levels of CO2 than can be accounted for by atmospheric equilibrium alone. However, in our tanks it's perhaps best to try and maintain a stable CO2 concentration close to atmospheric equilibrium, and good surface agitation can help with this too.

Turnover
To filter or not to filter not only depends on your desired livestock levels and how densely you decide to plant, but also on the plant species you intend to grow. Plants with finely divided leaves such as Limnophila spp. for instance, will not thank you for allowing their leaves to become clogged with suspended sediment from substrate disturbance. So a good filter could prove an advantage especially if your livestock levels are relatively high. In a low-energy tank a filter that turns over about 5 times the tanks total volume per hour will suffice. However, having said that I tend to stick to the general rule of turnover for a planted tank, that is 10 times the capacity of the tank per hour. So for a 100 litre tank the filter should turnover about 1000 litres per hour. I use external canister filters since they have many advantages over internal filters, not least they are less conspicuous and have a larger and more versatile media capacity.

Peat Filtration
Whatever rate of turnover you decide to choose give some thought to the use of sphagnum moss peat in the filter. Peat filtration releases HS (humic substances) which have a number of beneficial functions in freshwater aquaria. Not least of these substances is DOC (dissolved organic carbon) which is an important source of CO2. However, if you are going to use peat filtration I would recommend that you don’t’ try to use it in conjunction with charcoal filter media. Charcoal is widely used for chemical filtration and is not compatible with the use of peat, since it removes DOC and valuable nutrients.

HS also keep micronutrients, such as iron, in solution and available to plants whilst at the same time safeguarding against metal toxicity. They are also beneficial for the reproductive health of fish, and can even prevent algal growth and kill harmful microorganisms.

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Mound Building. Credit Tim Harrison

Soil depth
Well that’s the basic components explained all we need to do now is put them together. Start by placing your slightly moistened soil in the bottom of the tank to a depth of around 2cm, you can slope it up toward the back to 4cm or so if desired. I've achieved excellent results with deeper soil but there is a danger it may become too anaerobic. Aquatic sediments are anaerobic by nature and macrophytes have evolved to grow in them but if the sediment is too devoid of oxygen plants have to work harder to uptake nutrients from them. Further, hydrogen sulphide may build up to levels that inhibit root development and therefore plant growth. However, hydrogen sulphide is unlikely to harm aquarium critters since it is quickly oxidised to harmless sulphates in the presence of oxygen.

Soil retainer
I usually allow a 1cm - 2cm gap around the edges, for cosmetic reasons and also to discourage unsightly algal growth up against the glass, especially blue-green algae or cyanobacteria as it is correctly known. Once this has been done I will cover the soil with a gravel tidy or soil retainer, but this isn’t essential. A soil retainer is a sheet of fine plastic mesh, the type usually used for greenhouse shading. Plants will naturally extend their roots down through the sand cap and soil retainer and in to the soil substrate below, often in a matter of days. The phenomenon is known a geotropism and occurs in response to gravity. The advantage of using a soil retainer is that it minimizes any soil disturbance and resulting turbidity during aquascaping, and ongoing maintenance.

Capping substrate
Cap the whole lot with about 3 cm of well washed gravel or sand, sloping to perhaps 4cm – 5cm at the back. A good choice is pool filter sand grade 6/14 or sand with an average particle size of about 3mm. Pool filter sand is composed of inert silicates that will not affect water chemistry. The size and rounded shape of the grains prevents compaction allowing water movement, nutrient transference, and gas exchange. This allows for a healthy oxidised microzone. That said, I've used everything from coarse gravel to fine sand and all to good effect too, so there is no need to compromise aesthetics for function. However, if the sand is too fine it effectively seals off the soil from the water column stopping nutrient transference, so additional fertilizer dosing will eventually become necessary.

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Soil Retainer. Credit Tim Harrison

Oxidised microzone
The oxidized microzone is the very thin highly aerobic surface layer of soil that interfaces with the water column. It is of huge importance in a soil substrate tank since it supports the hive of microbial activity needed to neutralise toxic substances and unlock nutrients.

Fertilisation and nutrients
Given the correct selection of slow growing plants such as Aunbias spp. it is not strictly necessary to add nutrients to lower energy soil substrate tanks, other than those provided by tap water and fish food. Fish food contains all the essential elements required for healthy plant growth. But I am not suggesting that you leave fish food to rot in your tank. If you feed your fish very well, what they don’t absorb they excrete in the form of small inorganic compounds, or in other words the nutrients that plants can use. Shrimp and snails also help by breaking down organic matter, including fish mulm, in to smaller particles and bacteria do the rest, unlocking even more nutrients.

Soil degradation?
Nevertheless, this often begs the question…surely the soil will degrade over time as nutrients are steadily depleted by vigorously growing plants? The answer is not necessarily. The soils I have recommended are largely composed of clay and peat and have naturally high CECs as they contain particles that readily attract and bind nutrients to them. Plants are then free to uptake the nutrients through their roots, in particular iron and other trace elements, and phosphorus which is rapidly absorbed. So providing your cap of sand is of a thickness and grade that allows adequate water movement and nutrient transference your soil substrate should retain enough nutrients to keep your plants happy almost indefinitely.

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Walstad Nature Scape. Scape by Tim Harrison.

Inorganic nutrient dosing
Plants will also absorb nutrients through their leaves, therefore, in addition I dose my low energy tanks with nutrients to supplement those derived through fish excretion. Typically, the weekly dose I use is around one fifth to one tenth of that recommended for high-energy tanks. The dose is small enough that ready made liquid nutrient formulations like TNC Complete are economical for me to use. This relatively low dosing regime also means that regular water changes are not needed. Instead simply missing a dose every so often, about once a month or two will suffice.

Dry salts
Similarly, dry salts can also be used particularly if a more economical alternative is required for larger aquariums and/or higher doses. The standard regime, for say a 20 gallon low energy tank, is to dose once every week or two with the following; 1/4 teaspoon of GH booster, plus 1/8 and 1/32 of a teaspoon of KNO3 (potassium nitrate) and KH2PO4 (monopotassium phosphate) respectively. The ratios can be scaled up or down to suit any size of tank. The above dosing regime presupposes that macrophytes in lower energy tanks grow 5 to 10 times slower than in higher energy setups, and it also assumes that “fish food” indirectly contributes about 80% to 90% of the nutrient load.

Bioavailable organic carbon
It is also possible to achieve even greater growth rates by dosing with bioavailable organic carbon and doubling or trebling the above nutrient doses. This is considered by many a high energy route, and to maintain a healthy equilibrium this dosing regime will also require larger and more frequent water changes; typically 25% to 50% once a week to remove the metabolites of increased photosynthesis and respiration, and to reset nutrient levels.

CO2
Similarly, there is absolutely no reason why a soil substrate shouldn’t prove beneficial as a planting medium in a higher energy setup as well. There isn’t any reason why soil substrate couldn't be used with eutrophic nutrient dosing, such as EI, and CO2 injection. After all many higher energy enthusiasts already use mineralized substrates, and the use of potting compost is not that much of a leap of faith when all things considered.

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CO2 & Soil. Credit Tim Harrison.

Soil synergy
In short there are many synergistic benefits to using soil substrate alongside nutrient dosing methods. For instance, soil substrates with a high CEC will also attract and bind inorganic nutrients added to the water column, where they will also be made available for root uptake. The high nutrient content of soil substrates can also act as a safety net, buffering against the occasional missed nutrient dose.

The aerial advantage
Floating plants such as Salvinia spp. and others that grow emergent or floating leaves, like Aponogeton natans. have the aerial advantage. The aerial advantage allows plants to harness relatively high concentrations of atmospheric CO2, and take advantage of much higher rates of CO2 diffusion; diffusion of CO2 in water is very slow by comparison. Plants with emergent leaves can also take advantage of higher light intensity which combined with greater CO2 uptake results in higher levels of photosynthesis and rapid removal of dissolved organic nutrients from the water column, which not only increases plant growth rate, it also helps to combat algae. Further, emergent plants are generally better at oxygenating the root zone, or rhizosphere, than submerged plants; this helps create an environment more conducive to healthy growth.

Soil/sediment metamorphosis
Newly submerged terrestrial soil goes through a number of chemical and biological changes before it becomes stable aquatic sediment. During these changes organic matter is broken down to form inorganic molecules, or the nutrients that plants can use; this process is often referred to as mineralisation.

Mineralisation of a submerged soil usually releases ammonia and other chemical compounds in to the water column where they can reach levels that are toxic to fish and invertebrates; but rarely to plants so it is usually safe to plant a newly set up tank immediately. The use of macrophytes as water purifiers is well documented, so apart from adding instant interest, planting heavily from the outset will help to reduce ammonia and other chemical compounds to non-toxic levels. The plants will also often benefit from the additional nutrient load and CO2 given off during mineralisation.

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Soil Substrate CO2 Tank. Scape by Tim Harrison.

Self-cycling method
I have always found that the ammonia given off during mineralisation is more than adequate to cycle a filter so now is the time to hook one up. This self-cycling phenomenon is in effect fishless cycling but without the hassle of dosing ammonia, or adding fish food and suffering the subsequent consequences of phosphate build up. There is also far less water testing involved.

Rate of mineralisation
Mineralisation can take up to 2 months to complete, but the actual rate is determined by a number of factors such as the organic content of the soil, water and soil chemistry, and microbial activity. Planting heavily from the outset also helps to reduce the length of time it takes for newly submerged soil to stop giving off ammonia since macrophytes release O2 and organic compounds through their roots which will greatly increase microbial activity, and therefore nitrification and denitrification. The existing bacteria on plant roots will also help inoculate the sediment and perhaps further speed the process on its way.

Soil equilibrium
Eventually an equilibrium is reached and the soil substrate will actually start to absorb ammonia/ammonium from the water column where it will undergo nitrification. When levels of ammonia, nitrite, and nitrate stabilize within acceptable levels it’s a sign that denitrification is also well under way. If Nitrate levels are still a little high a substantial water change is usually all that is required to make the tank habitable to fish.

Mutually inclusive processes
Overall levels of ammonia, nitrite, and nitrate always seem to stabilize within acceptable levels quite quickly, often within a week or two. So although it can take up to 2 months before mineralisation is complete it is not usually necessary to wait anywhere near that long before adding fish. In this respect it probably helps to think of mineralisation and tank cycling as two separate but mutually inclusive processes.

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Walstad Jungle Scape. Scape by Tim Harrison.

Mineralised top soil
An alternative to allowing soil to mineralise in situ is the use of MTS (mineralised top soil) or mineralised potting compost. MTS is thought to bind more bioavailable nutrients, and give your plants a better start whilst preventing the excessive release of organic nutrients. Excessive organic nutrient release combined with too much light, can lead to algal outbreaks. Further, MTS is often considered less prone to disturbance during scaping and subsequent maintenance. The internet provides a wealth of information on how to mineralise soil, but the methodology after Aaron Talbot is perhaps the most widely used. It simply involves a process of repeated soaking, rinsing and drying, typically four cycles long. Eventually, the soil is sifted to remove large particles and achieve a fine grained well sorted substrate.

Finally, powdered clay can be added. Its flocculating properties help bind the soil particles and its high CEC and iron content benefit plant growth. Powdered or pelleted Dolomite can also be added as a source of the nutrients magnesium and calcium, and if necessary to buffer pH, and similarly potash can be added as a source of potassium. However, mineralising soil is a lot of messy work, and on balance I prefer to do it in situ, mainly because it's far less labour intensive but also because of the synergistic benefits already discussed further above. Not least of these is the evolution of CO2 as the organic matter in the soil decomposes, and as also previously mentioned, it’s a convenient way to cycle a tank.

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Walstad Nature Scape: Flowering Anubias. Scape by Tim Harrison

Suitable plants
There are many aquatic plant species that will grow vigorously and thrive in just soil alone and whatever additional nutrients tap water and fish food have to offer, and for years without showing any signs of nutrient deficiency. And there are even more that will benefit from the addition of water column nutrient dosing. But growing plants successfully is also about choosing those that best suit your unique aquarium conditions. One approach is to plant as many different species as possible and then let them fight it out. That way it soon becomes obvious which plants thrive in your unique aquarium conditions and which ones to avoid in future. The following low-energy plant list is by no means definitive but it should give you a good place to start; most are very easy to grow:

Anubias spp.
Aponogeton natans/crispus
Bolbitis heudelotii
Ceratopteris
spp.
Cryptocoryne spp.
Echinodorus
spp.
Egeria densa
Fontinalis antipyretica
Hygrophilia
spp.
Lilaeopsis brasiliensis/novae-zelandiae
Ludwigia repens/natans
Microsorium pteropus.
var.
Pistia stratiotes
Salvinia auriculata
Sagittaria
spp.
Taxiphyllum spp.
Vallisneria spp.
Vesicularia dubyana

Give it a go!
I hope this article has informed, and inspired even the most dedicated dyed in the wool technophiles amongst you to set up a hybrid-energy soil substrate planted tank. Why not let nature do some of the hard work for a change? You can still use most of your gizmos, and at the very least you will create a fascinating complement to your high-energy setups. At the very most you might even become a full blown convert. And for those of you new to the hobby or returning after an absence, consider the method before you take the high-energy plunge. Honestly, it really isn’t rocket science and once the basic principles are grasped the benefits are there for the reaping. If despite all you are still determined to set up a high-energy tank why not give some thought to using soil substrate anyway? Finally...the Zen bit, if you decide to give the hybrid-energy soil substrate method a go I hope you enjoy the journey as much as I have so far.

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Soil Substrate and Fertz. Scape by Tim Harrison.

Further reading:

The Barr Report http://www.barrreport.com/
Walstad (1999) Ecology of the Planted Aquarium. USA: Echinodorus Publishing.



Addendum: Low-energy lawns and the DSM...

Something else that seems to come up frequently is low energy lawns. So I thought it might be an idea to write an introduction and include it here as additional material.

Low-energy lawns and the Dry Start Method
One of the biggest bugbears of the low-energy way is the length of time it can take to establish a lawn of foreground plants. However, it is possible to give your plants a head start by using the DSM (dry start method). The internet is a valuable source of information on the DSM with a variety of methodologies achieving a similar goal. But for most it simply involves growing plants in a wet substrate for 2-6 weeks before the aquarium is flooded. This allows plants to use the aerial advantage to become firmly established. In addition, whilst plant roots are growing in they oxygenate the rhizosphere which accelerates the bacterial driven processes of tank cycling and substrate mineralisation.

The DSM has the added advantage of being algae free (no water), and of being less labour intensive. For instance, there are no water changes and nutrient dosing isn’t necessary, although fertiliser can be added to the substrate to help establish a lawn quicker. Foliar feeding with a dilute nutrient solution can also help, but if the solution is too concentrated it may burn plant leaves; I use 3 mls of TNC Complete per litre of water. But when all said and done, the key to a successful dry start is very high humidity, so all that’s really required is regular misting and a tank cover; clingfilm usually suffices. This ensures the plants leaves don’t dry out and provides ideal conditions for growth.

The methodology is usually as follows...

1. Add water to a level just below the surface of the substrate; don't let the water level raise above the top of the substrate, which can happen with daily misting.
2. Keep the tank sealed, but let fresh air in for 5 minutes every day to replace the old stagnant air, this may help prevent mould.
3. Spray and mist the plants.
4. Reseal.
5. Repeat daily for between 2 - 6 weeks during which time your lawn should become fully established, and then flood.

Nevertheless, the DSM is not without its downside. Looking at a tank devoid of water for several weeks can stretch delayed gratification to its limits. The humid conditions also favour mould growth, which can become a problem. Also, many plants don’t necessarily make the transition from emergent to immersed growth very well, particularly in a low-energy system. Therefore, it may help to achieve better results by choosing easy care, low maintenance plants such as Lilaeopsis brasiliensis, L. novae-zelandiae and Cryptocoryne willisii. Other plants such as Marsilea hirsuta, M. crenata, Staurogyne repens, and Micranthemum 'Monte Carlo', may not be as low maintenance but might still be worth a go. Plants nursery raised in their emergent growth form will be better suited to the DSM.

Low-energy lawns, bioavailable carbon or CO2 and DSM
Another way to establish a lawn in a shorter period of time is to simply go high-energy for a while and use bioavailable carbon or CO2 in conjunction with an appropriate high-energy fertiliser dosing and water changing regime. Once the lawn has been satisfactorily established both carbon and fertiliser can gradually be tapered to zero over a period of 2 – 4 weeks. This gives the plants time to adapt to low energy life; after which the rest of the aquarium can be planted. The method is even more effective if it's combined with the DSM, a la the Barr Report - Hybrid methods, fusing dry start + Excel with non CO2, which uses carbon for the first 2 – 3 weeks after flooding https://barrreport.com/threads/hybrid-methods-fusing-dry-start-excel-with-non-co2.4231/.

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The Dry Start Method. Scape by Tim Harrison.
 

Alastair

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Re: Zen and an Introduction to the Art of Underwater Gardeni

A great read and great for anyone starting out.

Didn't you write this troi?
 

Tim Harrison

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Re: Zen and an Introduction to the Art of Underwater Gardeni

Alastair said:
A great read and great for anyone starting out.

Didn't you write this troi?

Hi...well yes ok its a fair cop...I did... but for some very mysterious reason I couldn't submit it under my own name so I had to use my sons account, who incidental is also a very keen aquarist.

Troi
 

Tim Harrison

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Re: Zen and an Introduction to the Art of Underwater Gardeni

Thanks that is very kind of you to say so. I tried to steer clear of technical jargon and make it as easy to read and understand as possible.
 

sanj

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Re: Zen and an Introduction to the Art of Underwater Gardeni

I think it is a great article, a welcome addition with an alternative slant to the dominance of the EI method. I have a tank set up as "low tech" no co2 injection although there are differences, I use an external filter 500lph on a 60 litre tank and I have used tropica subsrate (contains sphagnum) overlayed with gravel and also large pockets of ADA at the rear.

I am hoping to be able to maintain a colony of gerts (Psuedomugil gertrudae "Aru II") in there, jungle planted so hopefully a few fry may survive and grow. :D
 

Tim Harrison

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Re: Introduction to Underwater Gardening with Soil Substrate

Thanks, I can't tell you how appreciative I am of your support. I am glad you noticed the alternative slant, there are just one or two things I do a little differently but they have the potential to make a significant difference to plant growth and aquarium health in general.

Beautiful fish, good luck with the fry.
 

plantbrain

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Re: Introduction to Underwater Gardening with Soil Substrate

Adding ferts into the sediment is a no brainer. Many balk at ADA aqua soil, but it's just rice paddy clay, we have hectares of it. In pot test I did at the lab, the ADA did the same as the Clay loam rice paddy soil with 4 weedy aquatic species. My old reservation is having 2 layers of sediment, I just do not like that part, but many are fine with it. I can wiggle my way around that by using ADA AS in a non CO2 tank also though :idea:

Likewise, you can alter EI and do reduced water changes, here's an example:
Once a month, 50% water changes, this one too:
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Hardly high labor or input.

Also, I dose 1x a week, about 1/10th of EI for this tankw hich is non CO2 and get water for evaporation only:
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Water change reduction can be done with ANY method. But there's more risk associated with it if you increase light, CO2 etc. So less light, and less CO2/no CO2 enrichment..........will help. For dosing, sediment sources are great regardless of the method chosen for dosing the water column. It will only make it easier and much simpler/forgiving, more wiggle room. This is true for both dosing and for reduced water changes....if you associate the need for water changes with the need to reduce NO3 or some other fertilizer based parameter. I honestly do not KNOW at what point that becomes a risk to livestock.

But I like to keep my tanks relatively clean and do not like water splashing all over when I work in them.
I'm a big advocate of water changes, but so is Amano, we both often suggest 50% weekly, and came at this amount/range independently, same for Discus folks and other breeding folks. They do not hurt.
But you can wiggle around them for sure. I wish the soil based Walstad tanks had some nicer examples, it would do a lot to sell the method. That's the biggest barrier I would say, having lots of folks that can display a nice non CO2, non Excel/easy carb dosed tank with soil.

Careful not to assume that EI does and cannot include soil or ADA As etc, most of my tanks use soil, so that's a vote of support for the soil. I would say soil enhances and adds synergistic effects with any water column dosing method. Soil or enriched sediments only enahnce water column dosing methods, making them easier and more forgiving. There was NEVER any 50% weekly water change REQUIREMENT in EI, it's merely a start point and folks can and likely should modify from there.

The same is also true for organic and clay soil usage.
Still, by advocating the negative risk and extra waste/labor doing large frequent water changes you run more risk to the average user.........than advocating the positive points for doing more frequent water changes, but we have cases where both work quite well. Same for non soil based sand only type sediments.
I would make a table of the + and - for the use of EACH method. There is a trade off for NOT doing water changes/doing them and/or using plain sand vs soil.

This may appeal to some folks, while others might prefer to be on the safe side.
Most understand and get the frequent water change, but many also would like to avoid them.
I think many just have not tried the soil sediments enough/yet and have some fear about using them.
The horticulture methods: pruning topping, mowing various species still allows for a high level of scaping to be done with soil also, you might want to touch more on that.

Good skill/instruction there will help a great deal with soil based sediments and avoid the messy results by many who move plants around like Chess pieces.

Still, I would/do advocate soil/enriched sediments regardless. Minimal input. Reduces the neglect potential, I often argue for soil/non CO2 methods as a "sustainable" method. Min input/output.
 

plantbrain

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Re: Introduction to Underwater Gardening with Soil Substrate

On the APD, Steve P has a soil obsession, you might find many of the links and articles useful:0

Note, much of this is from the 1990's, old stuff but........

http://home.infinet.net/teban/

I've used peat a lot myself in the past, so has Neil F and few other folks in the USA.
 

Tim Harrison

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Re: Introduction to Underwater Gardening with Soil Substrate

Tom…thanks for your comments. It seems our philosophy is very similar, but I can understand why it may not seem so at first. The objective is the same - to maintain a healthy planted tank - the only difference is that my approach is from the opposite end of the energy spectrum. The article endeavored to show that using soil substrates offers a range of possibilities and that it is up to the individual to decide on the level of energy investment they are happiest with in order to achieve their goals: but always within the context of providing a lower energy alternative to CO2 injection and nutrient dosing.

I have not long since returned to the hobby after some 25 years absence, and was doing things the “Walstad Way” over 35 years ago, as a child I hasten to add, so I am just getting started again. It had always been my intention to at least try and demonstrate the full potential of soil substrate with regards aquascaping and other possibilities, including inorganic nutrient dosing and perhaps CO2 injection as well, but I can only do so much with the limited time at my disposal.

The finished article originally included a section on inorganic nutrient dosing which would have perhaps given the reader an even wider appreciation of the potential of soil substrates. But I pulled it at the last moment because I felt uncomfortable advocating something I hadn’t tried myself. Not only, but also, I didn't think I could do it justice, and to be quite frank I wasn’t sure how well it meshed with the lower energy ideology of using a soil substrate. Incidentally, it was using your ideas circa 2005, similar to those you mentioned again in your post. I was contemplating revisiting the pulled section and including it in the article again, at some point later, but your welcome contribution has saved me the bother now. Nevertheless, I might still include something similar for the sake of convenience when I have more time.

Troi

P.S. thanks for the link, Steve's website is already bookmarked in my favourites list.
 

Brenmuk

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Re: Introduction to Underwater Gardening with Soil Substrate

I think it is a misconception that Walstad type tanks have to be low energy tanks. Diana Walstad says in her book that she puts her tanks next to south facing windows and I seem to remember either reading in her book or in one of her threads that she had one of her south facing windows enlarged to maximise the amount of sunlight her tanks were receiving.

Below is a link from someone who set up a large Walstad style tank next to south facing windows with 5x 100w lighting over 125 us gals. giving about 4w/gal plus sunlight. Towards the bottom of the link a further 6 lights were added!!

http://dataguru.org/misc/aquarium/125tank.html

My own experience with Walstad type tanks tells me that you get algae if there is too much light unless you have a very rich soil and are feeding loads to maintain high levels of nutrients.
 

Tim Harrison

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Re: Introduction to Underwater Gardening with Soil Substrate

Below is a link from someone who set up a large Walstad style tank next to south facing windows with 5x 100w lighting over 125 us gals. giving about 4w/gal plus sunlight.

That's a lot of wattage, do you think that author possibly meant 100 watts in total...?

100 watts of 6500K compact fluorescent light inside reflectors from the clamp on worklights... mounted on pvc and hung from the ceiling with chain and it's sitting in front of south windows

Interesting site nonetheless.
 

plantbrain

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Re: Introduction to Underwater Gardening with Soil Substrate

Troi said:
Tom…thanks for your comments. It seems our philosophy is very similar, but I can understand why it may not seem so at first.

I agree! It is much more similar(far more so) than dissimilar:)

The objective is the same - to maintain a healthy planted tank - the only difference is that my approach is from the opposite end of the energy spectrum. The article endeavored to show that using soil substrates offers a range of possibilities and that it is up to the individual to decide on the level of energy investment they are happiest with in order to achieve their goals: but always within the context of providing a lower energy alternative to CO2 injection and nutrient dosing.

I'm 110% with you brother!
I prefer helping folks in that sustainability direction.

Not that popular in the USA :silent:
The Land of Excess.

I use this idea to highlight higher production and less cost for farmers however, so professionally.....I can be more clever and help a bottom line. Aquarist? They love the dope, the CO2.

I have not long since returned to the hobby after some 25 years absence, and was doing things the “Walstad Way” over 35 years ago, as a child I hasten to add, so I am just getting started again. It had always been my intention to at least try and demonstrate the full potential of soil substrate with regards aquascaping and other possibilities, including inorganic nutrient dosing and perhaps CO2 injection as well, but I can only do so much with the limited time at my disposal.

And before you and me and Diana, there was Dorothy Reimer in the USA and dozen of folks in Europe, much of this history has been lost. Darrel is a big proponent here on the site, as was a Certain feller Jeff W as I shall call him, but he liked the gas.

Time factor is a great angle to use, less water changes, less labor input, more sustainable, you can have more tanks with the same amount of labor........ the argument in favor this approach, as Diana makes a convincing case for in her book, is strong.

The finished article originally included a section on inorganic nutrient dosing which would have perhaps given the reader an even wider appreciation of the potential of soil substrates. But I pulled it at the last moment because I felt uncomfortable advocating something I hadn’t tried myself. Not only, but also, I didn't think I could do it justice, and to be quite frank I wasn’t sure how well it meshed with the lower energy ideology of using a soil substrate.

If you'd like examples and background there, I'd be happy to offer some info and experiences. I wondered if I could isolate and learn more about the non CO2 method by using inert sediments. Turns out, it's very easy and the estimation of the nutrients is fairly easy and plenty of wiggle room........

Incidentally, it was using your ideas circa 2005, similar to those you mentioned again in your post. I was contemplating revisiting the pulled section and including it in the article again, at some point later, but your welcome contribution has saved me the bother now. Nevertheless, I might still include something similar for the sake of convenience when I have more time.

Troi

P.S. thanks for the link, Steve's website is already bookmarked in my favourites list.

Yea, he kinda went awol after the lawsuit on the APD since he sides with the plaintiff, understandably.....not many friends after that.

But most of the musings are good for references.

He came around the time when many hobbyists were all water column crazy and having advances there.
Neil, SFBAAPS group and myself had used peat often and I used up till around 2004 or so........
 

plantbrain

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Re: Introduction to Underwater Gardening with Soil Substrate

Brenmuk said:
I think it is a misconception that Walstad type tanks have to be low energy tanks. Diana Walstad says in her book that she puts her tanks next to south facing windows and I seem to remember either reading in her book or in one of her threads that she had one of her south facing windows enlarged to maximise the amount of sunlight her tanks were receiving.

Below is a link from someone who set up a large Walstad style tank next to south facing windows with 5x 100w lighting over 125 us gals. giving about 4w/gal plus sunlight. Towards the bottom of the link a further 6 lights were added!!

http://dataguru.org/misc/aquarium/125tank.html

My own experience with Walstad type tanks tells me that you get algae if there is too much light unless you have a very rich soil and are feeding loads to maintain high levels of nutrients.

I agree here also, they can be whatever you want.........I have a nicer looking non CO2 approach on my ADA tank.......and with emergent plants....you can go nuts.......with the light and also........the uptake by the plants.
since light and CO2 are much more available..........nutrients can be dosed more liberally even.

I use pennywort as a indicator plant for ferts since it is a real Nitrogen hog and I've grown it emergent on various tanks for some 15 or more years now. Once it tells me its time to dose, I add basically the same ratio of ferts to any tank, but just less/more etc.

Still, one of the main issues with non cO2 tanks, is showing them off like ADA does....and that.....will sell a method far more than ANYTHING we can write on line. This requires good photography, good horticulture, scaping skills, creative, and passion for the method.

Many that like such methods tend to be neglectful, hands off, let's see where this goes type of approach.
Amano sort of does this with his own large tank in his home. I do it on 2-3 of my tanks, I have emegrent marine plant growth, non CO2 emergent growth and then CO2 enriched tanks with some emergent growth as well.

tresizedreef928.jpg

6aa5e984.jpg

oldschoolwasabikusa.jpg

ca09afe4.jpg


My direction is different than many using such methods.
Another example of a more traditional non soil based tank without water changes for a year etc.........
nonCO2cube4.jpg

cubenonco21.jpg


Or anything from NBAT from 1970 back.......
Some of those are really good.
 

sanj

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Re: Introduction to Underwater Gardening with Soil Substrate

I have my 60 litre non CO2 tank in my study which happens to have a south facing window with verticle blinds. I just used my PAR meter this morning and the readings can be very high, close to 400, but constantly changing with the cloudy weather, went down to 22. Thats a lot of fluctation from PAR levels suitable for sps corals right down to barely adequate for photosynthesis.

Normal lighting is 6 hours in the evening with 22 watts from compact flourescent lights.
 

sanj

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Re: Introduction to Underwater Gardening with Soil Substrate

Many that like such methods tend to be neglectful, hands off, let's see where this goes type of approach.
Amano sort of does this with his own large tank in his home. I do it on 2-3 of my tanks, I have emegrent marine plant growth, non CO2 emergent growth and then CO2 enriched tanks with some emergent growth as well.

I am also using red mangroves, but on my freshwater co2 enriched tank. Just creating another dimension, I dont know what impact it will have on the system other than being a nutrient exporter, but then they do grow slowly.
 

plantbrain

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Re: Introduction to Underwater Gardening with Soil Substrate

Try the black mangrove, it should be better for FW systems, I've seen really nice displays in Tampa FL's public aquarium using that species, grows faster etc.
 
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Antipofish

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Re: Introduction to Underwater Gardening with Soil Substrate

sanj said:
Many that like such methods tend to be neglectful, hands off, let's see where this goes type of approach.
Amano sort of does this with his own large tank in his home. I do it on 2-3 of my tanks, I have emegrent marine plant growth, non CO2 emergent growth and then CO2 enriched tanks with some emergent growth as well.

I am also using red mangroves, but on my freshwater co2 enriched tank. Just creating another dimension, I dont know what impact it will have on the system other than being a nutrient exporter, but then they do grow slowly.
I used to love seeing mangroves in a marine tank so its interesting to know that they work in a freshwater aquarium also. Do you have any pics of yours ?
 

Tim Harrison

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Re: Introduction to Underwater Gardening with Soil Substrate

The main thrust of my article concentrated on the lower end of the energy spectrum. However, Tom Barr’s contribution to the tutorial thread shows that soil isn’t just the preserve of the lower energy setup. There is absolutely no reason why a soil substrate shouldn’t prove beneficial as a planting medium in a higher energy setup as well, and everything in between. It’s simply a matter of finding the right balance between nutrients, CO2, and lighting to achieve a desired outcome, wherever it falls across the energy spectrum. For instance, there isn’t any reason why soil substrate couldn’t be used with full EI and all it entails including CO2 injection. After all many higher energy enthusiasts already use mineralized substrates, and the use of potting compost is not that much of a leap of faith when all things considered…and a whole lot cheaper and much more beneficial to plant growth and aquarium health in general.

In short there are perhaps many synergistic benefits to using soil substrate alongside nutrient dosing methods. For instance, soil substrates with a high CEC (cation exchange capacity) will draw dosed inorganic nutrients from the water column where they will become available to plant roots. Research shows that given relative concentrations in the water column many aquatic plant species will preferentially uptake most of their nutrients from the substrate. This also explains why soil substrates are capable of promoting vigorous plant growth over a period of several years using “fish food” (see article) alone and without inorganic nutrient dosing, particularly those containing high ratios of clay and/or peat. The high nutrient content of soil substrates can also act as a safety net, buffering against the occasional missed nutrient dose, and dosing mistakes.

Benefits of using a soil substrate can also include a reduction in energy consumption since, as I have already mentioned in the article, as the organic matter in soil substrate decomposes it releases CO2 in quantities that may well reduce the need for CO2 injection or actually render it completely unnecessary depending on the desired level of energy input and output. The same could be said for nutrient dosing. The quantity of nutrients and frequency of dosing could be reduced to a fraction of that required by full EI. Further, nutrient dosing could be used on its own without CO2 injection, or for that matter with or without the addition of organic carbon additives. Experimenting with nutrient dosing on its own or with any of the above combinations could even prove beneficial to those already achieving great results using soil substrate on its own in a lower energy setup who do not want to go down the whole hog eutrophic dosing and CO2 route.

Tom has written on this very subject and, for say a 20 gallon tank, he recommends dosing once every week or two with the following; 1/4 teaspoon of GH booster, plus 1/8 and 1/32 of a teaspoon of KNO3 (potassium nitrate) and KH2PO4 (monopotassium phosphate) respectively. The ratios can be scaled up or down to suit any size of tank. This relatively low dosing regime also means that there is no need to reset nutrient levels with the regular water changes essential to the success of EI and other eutrophic dosing methods; instead simply missing a dose every so often, about once a month or two, will prevent nutrient build up. The above dosing regime presupposes that macrophytes in lower energy tanks grow 5 to 10 times slower than in higher energy setups, and it also assumes that “fish food” indirectly contributes about 80% to 90% of the nutrient load.

Tom also states that it is possible to achieve even greater growth rates by dosing with bioavailable organic carbon and doubling or trebling the above nutrient doses. However, to maintain a healthy equilibrium this dosing regime will also require larger and more frequent water changes of 25% to 50% up to four times a month to prevent nutrient build up. But as I have already mentioned, when discussing other parameters, it all boils down to the level of energy you are happy to commit to in order to achieve your desired goals.

Next time you plan a new setup consider soil substrate. It should be a serious contender regardless of where your proposed set up falls along the energy spectrum.
 

gmartins

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Re: Introduction to Underwater Gardening with Soil Substrate

Hi Troi,

really nice post with lots of interesting information. I have no doubts that soils can be used in any situation: high to low energy. This has been tested with amazonia. So soils should not be much different - maybe richer in the long-term and probably less expensive.

anyways, just a detail:

Troi said:
For instance, soil substrates with a high CEC (cation exchange capacity) will draw dosed inorganic nutrients from the water column where they will become available to plant roots, which is the preferred mechanism of nutrient uptake for most aquatic plants.

that roots are the "preferred" mechanism of nutrient uptake in aquatic plants is not necessary true as is demonstrated by this study:

Rattray MR, Howard-Williams C, Brown JMA (1991) Sediment and water resources of nitrogen and phosphorus for submersed rooted aquatic macrophytes. Aquatic Botany 40: 225-237

under oligotrophic conditions, a rich sediment positively affected plant growth. However, under eutrophic conditions, there was no difference in plant growth in sediment-rich and sediment-poor substrates. Plants took all the nutrients they needed from the water column.

cheers,

GM
 
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