# Lava rock vs Charcoal



## singhm29 (Jun 28, 2009)

From my understanding charcoals primary function in most substrate mixtures is to add moisture retention and help oxygenate the substrate. It is also quite porous. I have used lava rock for backgrounds but never as an addition for substrate and now that I look at it I don't see why it would be a bad candidate once it was crushed down to a usable size. Aside from the nice aroma charcoal provides is there anything else that lava rock severely lacks?


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## Pumilo (Sep 4, 2010)

This was touched on here http://www.dendroboard.com/forum/parts-construction/63915-truth-about-abg-mix-9.html

Specifically, check out Ed's comment here.


Ed said:


> Look up terra preta....
> 
> Ed


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## singhm29 (Jun 28, 2009)

Very interesting, did not know charcoal offered that kind of soil amendment value. Although this tidbit was particularly interesting 

"..Several experiments demonstrate that uncharged charcoal can bring a provisional depletion of available nutrients when first put into the soil - until its pores fill with nutrients. This is overcome by soaking the charcoal for 2 to 4 weeks in any liquid nutrient (urine, plant tea, etc.)..."

Preparing the charcoal for a few weeks sounds very interesting. Possibly using cricket droppings as the nutrient source or any other feeder waste product?

I agree that outright replacement of charcoal with lava rock might not be the smartest thing but am I the only one who sees the merit this cheap substrate ingredient could hold?


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