# is clay really needed in a dirt substrate?



## Zapins (Jan 7, 2006)

The simple answer is no you don't need to use it, and even when you do use it it doesn't help out in any meaningful way compared with not using it. Pure soil capped with some gravel will grow your plants equally well and is less hassle/expensive.


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## HuntCast (Aug 25, 2013)

Clay is for iron. Gives that little extra to the red plants. You can get by without it, but why not use it? Anywhere that has craft supplies will have red clay. Just make sure it is real and not plastic.


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## ForensicFish (May 19, 2013)

I agree with why not use it? It can only help. If you can't find any clay at your arts and crafts store buy some fluorite or laterite from a local fish store or buy it online.


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## tgold (Aug 23, 2012)

The clay mix acts as a bond for the topsoil and prevents it from clouding the water. If the plants are not uprooted or moved once the tank is filled, this should not be a problem. Depending on the region, digging down more than the depth of a shovel should produce clay soil. This soil can be tested by soaking it in water, if it stays in a clump and does not dissolve and cloud the water, then it can be used as clay.


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## Fletch (Mar 18, 2004)

Unscented, NON clumping cat litter is 100% clay (read the lable). It is used as cat litter because it is very absorbent (lots of surface area) and has very high Cation Exchange Capacity (CEC) which helps it bind urea and smells. High CEC is very useful in aquarium substrate because it binds nutrients, removing them from the water column, and only releases them when near a root, or the concentration of that nutrient gets low. You need to wash the cat litter in cold water to remove the very fine dust. I put 2 or 3 cupfuls into a pail, and rinse several times until the water stays fairly clear and you can see the clay at the bottom of the pail. I use a mix of 10% clay, to 90% Miracle Grow Organic Potting Soil. I also wash the potting soil, but that takes a while. I add about 1/4 pail full of MGOPS and fill the pail with cold water, stir, and then leave overnight. It takes that long to hydrate properly. I do this 3 times. Then I squeeze the water out of the soil, and dry it in a large foil pan for storage, or put it directly into a tank, add 10% washed clay, and then cap with gravel or sand. I am not sure if 10% clay is optimal, its just what has been working for me. Anyone else have experience with cat litter clay? What percent do you use?


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## GadgetGirl (Oct 11, 2013)

I used Oil-Dri, which is basically the same as Kitty litter in about the same proportion as you. I never had any ammonia. 
My question is does this type of clay provide the same benefits as red artist clay? 

Sent from my Nexus 7 using Tapatalk


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## CluelessAquarist (Apr 5, 2014)

HuntCast said:


> Clay is for iron. Gives that little extra to the red plants. You can get by without it, but why not use it? Anywhere that has craft supplies will have red clay. Just make sure it is real and not plastic.



Do you know if the clay has to be red clay? I have some clay from my pottery class, it's stoneware, but it isn't red.


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## Hoppy (Dec 24, 2005)

Red clay, as well as laterite, were originally suggested as a way to get more iron to the plants. I think we know now that iron in red clays is not that available to plants. But, those who started using it believed they had much better plant growth as a result. That might have been due to the high CEC of clay particles, rather than more iron. I think you are better off supplying iron as chelated iron in a fertilizer trace element mix, and using something like kitty litter or sports field amendment instead of just clay in the substrate.


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