I found the Holy Grail   4 comments

OK here it comes….

Made in the USA, will be readily available, super light, good color, made from a renewable resource.


Three cubic foot bag, about the size of two bags of akadama. About 1/4 to 3/8 inch (10mm)

$17.95 a bag

100% recycled glass. I looked at this stuff and thought it was pumice from a brown volcano. Imagine my surprise when it was made from a machine and from recylcled glass.


There is a store locator on the “About” tab





I have taken a picture of the bag since the bag is vague on the size. I have taken the one foot to the third power to mean 3 cubic feet. If the Home company says its two cubic feet then so it is. This is what I had to go by. There has been some mention of size on some forums as well as my blog here. It is comparable in size to most of the soil making components out there. It is just a tad larger than some, but it is actually the size soil should be. Most substrates like akadama, turface, haydite, kitty litter and the like are much too small a particle size. I raised a stink on the Bonsai Study Group a month or so ago on a post titled “Bad Soil, Bad Root”. There was not much related into why the soil was bad, just that it was clogged and did not promote a gaseous exchange of oxygen to the roots. What was used may have been OK when it was fresh, but broke down or was too small in the first place. Substrate is substrate. It does not matter much what it is as long as the particle size promotes some modicum of moisture retention, is gas permeable, and has some porosity to colonize bacteria. That can be sintered glass, (as here), or clay balls, (akadama). The plant does not really care what you plant it in as long as you meet those criteria mentioned above. The bag details on volume. Anyone care to take a stab?


This is how the glass looks compared to some other substrates I use.

At 12 oclock- Akadama

At 3 oclock- Mocha lava

At 6 oclock- Growstone

At 9 oclock- Lava

I use larger lava on larger trees up to 3/8 size. This is about 1/4 or smaller. Same with the akadama. The mocha lava is a full 1/4 inch in size.


As far as price? This is a hydroponic growing medium intended to be used in the cultivation of indoor cannibis. I have seen plant nutrient solutions sell for $129.99 for a quart bottle. I am sure this will be priced differently regionaly and from store to store with in same towns. Lets just say that most of these “products” are subject to “whatever the traffic will bear” pricing, and unfortunatly most of these people have more cash than sense. So there you go.


28.3 liters is one cubic foot. So this bag is one cubic foot. I also poured a cup full into a tub of water and it does float. Of all the particles about 7 sunk. I filled a bonsai dish with the substrate and watered it with a waterwand and the water flowed right thru. While it does float it seems to have enough weight on its own to allow water to flow thru. If the pot did not have drainage holes I am sure it would float right over the pot edge. Of course like any true pumice it floats. I do not see this as an issue when used by itself or mixed into a substrate blend. Doesn’t bark float??? oh yea thats right it does.

New Update

A tree grown in 100% Growstone and the results


Posted February 5, 2013 by California Bonsai Art in Uncategorized

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4 responses to “I found the Holy Grail

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  1. pretty exciting stuff Al!

  2. how big are the pieces? can they be busted up to smaller sizes? am i asking too many questions?

  3. Very interesting. I remember reading about this on George Muranaka’s blog (http://muranakabonsainursery.blogspot.com/2011/11/freezing-weather.html). I wonder if he has done any more experimenting with them. Do you think they will function similar to lava or pumice in a soil mix? Even if they do, like you mentioned, their color, weight and sustainability may be reason enough to use them in place of lava or pumice.

    Thanks all the practical information you are providing.

  4. Interesting. Please let us know how it works

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