# Loam soil ok to use?



## JonnyThe (Apr 27, 2007)

I'm thinking of changing my tank to a soil based substrate. I called in to a landscape supply yesterday and the only topsoil they had which didn't contain too much organics was a top-dressing loam with a small humus content. I took one look and thought it's basically just sand. But he said "trust me, you can grow garden plants in that and there's a fair bit of humus in it." He also explained that in the pits where they prepare the soils, this stuff is the first layer after the grass is removed from the top. Nothing else is added. So I bought a sample and after soaking some, sure enough there's some grass roots and stuff in it. But it just looks like "brickies" loam in the bag. Would this be too sandy/infertile for an El Natural setup? All the bagged potting soils around here have added ferts and stuff. And our backyard topsoil seems to have way too much clay in it. Or is clay not that much of a problem?


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## Tony65 (Jun 3, 2006)

Here's a link on top dressing loams

It seems to be ok for growing grass on golf greens 

Clay is good - maybe you could mix some of you backyard soil into the sandy loam?


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## JonnyThe (Apr 27, 2007)

Yes, I was thinking of mixing it with some of the backyard soil. But after doing some jar tests with the loam I don't think I'll use it. It's very cloudy and it would take ages to try and rinse it. And that would remove too much of the "goodness", I think.

What about adding a little compost to our backyard soil and mineralizing it? How much is too much? I have read of people using about 5% compost but others have said that amount could cause problems. And then Diana has used mushroom compost hasn't she?


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## Tony65 (Jun 3, 2006)

JonnyThe said:


> Yes, I was thinking of mixing it with some of the backyard soil. But after doing some jar tests with the loam I don't think I'll use it. It's very cloudy and it would take ages to try and rinse it. And that would remove too much of the "goodness", I think.


If the loam, capped with your gravel/sand choice, didn't settle after a day or so then it's probably not suitable.

Did you do a stand alone jar test on your backyard soil too?

I can't advise on adding compost as I haven't tried it. But there's nothing stopping you running a jar test on that mix as well.


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## JonnyThe (Apr 27, 2007)

Tony65 said:


> Did you do a stand alone jar test on your backyard soil too?


Yes, and it takes even longer to settle because of the clay. I'm a little worried that because it's a "heavy soil" it will become anaerobic quickly. And it will cloud the water immensely if plants are moved. I know with soil like ours, the addition of a little compost helps bind the finer particles together so there is less cloudiness. But I think it might be better to just find a more suitable topsoil.


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## Tony65 (Jun 3, 2006)

If you move plants about most soils will cloud the water to a degree, but you can add mechanical filtration to remove this quickly after doing any "gardening".

You can usually find suitable loam based composts/topsoil at garden centres or hardware stores. If we know the region where you are based the people on this forum may be able to suggest some suppliers.


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## dwalstad (Apr 14, 2006)

JonnyThe said:


> Yes, I was thinking of mixing it with some of the backyard soil. But after doing some jar tests with the loam I don't think I'll use it. It's very cloudy and it would take ages to try and rinse it. And that would remove too much of the "goodness", I think.
> 
> What about adding a little compost to our backyard soil and mineralizing it? How much is too much? I have read of people using about 5% compost but others have said that amount could cause problems. And then Diana has used mushroom compost hasn't she?


When you do the jar test, I trust that you are adding the water such that the soil layer is not disturbed. This seems obvious, but I have heard complaints about water cloudiness only to learn later that the hobbyist was blasting the water into the substrate. For jar tests, I place a little piece of aluminum foil over the substrate to keep it from being disturbed when I pour in the water.

Well-digested compost is a good thing to add with soil. I think you can add much more than 5%. After all, potting soil is ofter over 50% organic matter. Whether the soil works or not may depend less on the soil type and more on how many plants, the plant species (floating plants), light intensity, and water hardness.

Again, we are talking about an ecosystem with multiple variables. You may have to work it out for your own water, lighting, and planting conditions. That's the challenge (and fun) of having a natural aquarium.


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## JonnyThe (Apr 27, 2007)

Well I'm not sure about the cloudiness in the test jar but I feel the soil would cause too many problems in the tank.

I've done a little more reading on compost and am carrying out some experiments. I threw some dry, sieved, well matured compost into a bucket of warm water, gave it a little stir, then removed all the floaties and poured the water off. After doing this several times what's left is a fairly heavy "soil" which sinks well and doesn't cloud water at all. After soaking for several days to remove the excess amounts of ammonium, nitrites and tannins, I've slowly been adding a thin layer to the bottom of my 2 gal shrimp/snail biotope. It settles out perfectly and looks great. Not only that, but the four tube-building caddisfly larvae now have nice black houses. And if they don't mind it then it can't be too bad.

Do you think a substrate prepared as above, maybe with a few more steps to "stabilise" it more, would work in a smallish tank with no circulation? Or would it break down relatively quickly and cause problems? Diana, didn't you have a tank with mushroom compost in it? How long did it run for?


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## aquabillpers (Apr 13, 2006)

"Mushroom soil" is what is left after the mushrooms have been harvested. It has almost no N-P-K nutrients left in it and probably has very little organic matter.

As such, I'd think it would make a good soil substrate, but I've never used it.

I also would like to hear what Diane has to say about her experience with it.

Bill


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## JonnyThe (Apr 27, 2007)

aquabillpers said:


> It has almost no N-P-K nutrients left in it and probably has very little organic matter.


You sure about that Bill? Fungi don't use the same nutrients as plants do.

Wikipedia gives NPK ratio as 0.7 : 0.3 : 0.3
American Mushroom Institute gives it as 2 : 1 : 1, pH 6.8

It's highly variable, just like your average garden compost, but I'm pretty sure they are both similar with respect to NPK ratios and other plant nutrients. I think mushrooms drain more nitrogen from the media than anything else.


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## aquabillpers (Apr 13, 2006)

JonnyThe said:


> You sure about that Bill? Fungi don't use the same nutrients as plants do.
> 
> Wikipedia gives NPK ratio as 0.7 : 0.3 : 0.3
> American Mushroom Institute gives it as 2 : 1 : 1, pH 6.8
> ...


Yes, Johnny, I'm pretty sure. (I can always be wrong, though.  ) I understand that mushrooms are heavy and efficient feeders, and when they get done there isn't much left.

"Mushroom soil" is also sold as "spent mushroom compost (SMC)" or "spent mushroom substrate (SMS)". It is intended to be used as a mulch or a soil amendment. http://www.americanmushroom.org/compost.htm

It doesn't have a lot of nutrients in it, and so it would seem to be a good substrate material, pending Diana's comment on her experience.

Bill


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## JonnyThe (Apr 27, 2007)

Well I don't know then. Our garden books say it's rich in nutrients (values similar to what I posted). Several organic gardening sites say it's too rich for direct application to new plants or seedlings, due to the high amount of free nutrients. And some say it's better to "weather" the compost for several months to leach the excess salts.

Also this is interesting. The SMS used in the trials had an NPK of - 2.75 : 1.5 : 1.5
I think it says somewhere in the pdf that nitrogen is slowly released but P and K can rise to excessive amounts in soils if used continuously.

So if all this is true, then I think using weathered - maybe even soaked - mushroom compost might be safer in an NP tank. Or maybe mixing it with a loam soil like mine 

Sounds like great stuff though.


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## dwalstad (Apr 14, 2006)

JonnyThe said:


> Do you think a substrate prepared as above, maybe with a few more steps to "stabilise" it more, would work in a smallish tank with no circulation? Or would it break down relatively quickly and cause problems? Diana, didn't you have a tank with mushroom compost in it? How long did it run for?


Sorry that it took so long to answer your letter. I used potting soil that contained mushroom compost. This was only one of the many ingredients.

I suspect it would have a little less N than kitchen compost, but folks we may be splitting hairs here.


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