# Mineralised Soil Underlay Mix?



## Mxx (11 Sep 2011)

I'm looking at making up my own underlay soil mix, and am planning on using either worm castings, or a mix of composted manure and mineral garden soil, or possibly all three together. I'd be boiling the mix for 15 minutes (outdoors) once I add the other ingredients so I'm not worried about the ammonia/etc as that should immediately mineralize it. I'm also thinking of adding a little sand to give it a little weight, 15% green powdered clay to flocculate it. And following the boiling I'll let the entire mix evaporate to a fairly solid mud form, or possibly an altogether dry form which I can then use as powder. 

I'll add a sprinking of Dolomite Lime, Potash, fritted trace elements, and Micronized Iron as well. before I'd put the MTS down in the tank, unless I should keep it in the mix instead? Does that all seem like it would work? I was also considering adding some peat, but don't want it tinging the water I guess, and it can overeact with the iron. And then I'll cap that with something similar to 3M ColorQuartz Sand. However, I was worried that using composted manure would add too much sulfur and risk problematic Hydrogen Sulfide production?

And though I know they're not considered necessary now in terms of keeping plant roots warm, I'm still thinking I'll use substrate heating cable to keep a little flow in the substrate to try and keep allelochemicals flushing out, but would that flush out the nutrients as well, and make them available to algae instead of the plants?

The only nutrients I'd plan to dose in the water column would be Potassium, Calcium, and Magnesium. 

I based the plan in no small part on this article, though I varied from its advice as well - http://home.infinet.net/teban/substrat.htm


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## He-Man (11 Sep 2011)

I use garden soil from grassed area in garden that I know has been untouched by either fertilizers or pesticides for minimum one year, I spade roll up the turf and dig and bag it, if I go deep enough I can collect some iron rich subsoil to sprinkle in with the final mix of...3 parts garden soil, one part peat mix - the mix consists of two parts sphagnum moss peat, one part perlite and a handful of potters clay pieces, vermiculite and one of subsoil but if with flora pol or laterite or whatever then as instructed on box
an inch or two of this on top of an inch of plain sand and a heat cable from garden centre fifteen pounds and sandwiched down with black sand and 2mil gravel - a dark one
Somethings compelling me to steer you away from manure but I have no proof it's wrong, I once had that idea too but not sure it would be neccessary and I never carried it out. maybe it has been done before?
I must add that my latest use of soil as a substrate, I bought pond soil to try it out as I had injured my back and couldn't get any one to dig for me ...which seems to have been a good choice so far  two months and one day...now Plants are thriving and havent even been able to afford co2 system for it yet


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## Mxx (11 Sep 2011)

Thanks, um, He-Man, 

Manure isn't recommended at all for various reasons, including it being far too labile (will undergo too much change), it will eat up a lot of oxygen while changing, it can release a lot of ammonia, etc. However, if you boil it for 10-15 minutes which is one way of mineralizing soil quickly, then that should already complete its necessary transformation immediately and leave you with a very rich stable substance. Whether that is still to high in other things such as phosphates and sulfates is a different question. I have a bag of 'composted stable manure' in my garden, which looks to be pretty good quality rich soil itself, but even though it says it is stable I'd still want to boil it to make sure. But I might be better off just sticking with worm castings instead, even if that is a little more costly. 

To clarify, I'd be aiming for a Walstad type low-tech substrate, which itself undergoes a certain amount of transformation slowly and releases Co2 directly to the roots of the plants. And to achieve that you need to use organic soil, instead of the mineral soil which you'd typically find in the typical garden which is at most 5% organic soil. So with a fair percentage of organic soil I might get great plant growth without the trouble of using pressurized CO2. 

Interesting recipe you have though! What do you feel the peat does for you? And does that cause you any problems such as releasing tannins when used under the substrate? And do you happen to have any particular algae problems such as green water ever? I'm still wondering whether substrate heating cables result in the nutrients getting pumped out of a fertile substrate into the water?


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