Some facts about bonsai soil

[GroveKeeper]

Sifted wood chips is a bad idea. As it decomposes, it removes nitrogen from the soil. If you like the look, use sifted orchid moss as a top dressing.

I dont see how a top dressing of wood chips would significantly effect the amount of nitrogen content of the lower level of the substrate. I use regular liquid fertilizer that probably isnt lingering in the wood chip layer long enough to give up that much nitrogen.

Also... I dont like the orchid moss as a top dressing. It builds up a semi impermeable coating of algae in my climate.

 

[Adair M]

I dont see how a top dressing of wood chips would significantly effect the amount of nitrogen content of the lower level of the substrate. I use regular liquid fertilizer that probably isnt lingering in the wood chip layer long enough to give up that much nitrogen.

Also... I dont like the orchid moss as a top dressing. It builds up a semi impermeable coating of algae in my climate.

I thought he was putting wood chips in the mix, and as a top dressing.

Wouldn't a top dressing of wood chips generate the algae, too?

It's easy to pull off the orchid miss and replace it.

 

[Smoke]

Akadama is not clay.

Says who?

My akadama clay pot.

Every person on the California coast makes sticky muck for rock planting from akadama.

I think you need to do some reading on just what clay is?????

 

[Smoke]

Bentonite is an absorbent aluminium phyllosilicate clay consisting mostly of montmorillonite. It was named by Wilbur C. Knight in 1898 after the Cretaceous Benton Shale near Rock River, Wyoming.[1][2]

The different types of bentonite are each named after the respective dominant element, such as potassium (K), sodium (Na),calcium (Ca), and aluminium (Al). Experts debate a number of nomenclatorial problems with the classification of bentonite clays. Bentonite usually forms from weathering of volcanic ash, most often in the presence of water. However, the term bentonite, as well as a similar clay called tonstein, has been used to describe clay beds of uncertain origin.

 

[markyscott]

Akadama is not clay.

Akadama is a volcanic soil - it is comprised of partially to completely altered tephra deposits of volcanic ash and pumice. It's parent material was from arc volcanics, probably andesitic in composition like those in the Cascades. Remnant pumice grains are apparent in several bags I've bought, but generally the pumice and ash are nearly completely altered.



The pictures you may have seen of the akadama mined in Japan have layers - a dark organic-rich layer on top, then the red akadama layer, then the yellow kanuma layer. The boundaries between these layers are called soil horizons.



These kind of volcanic soils are called Andosols. An- is japanese for "dark" and -sol means soil. It refers to the dark, humic rich upper layer of the soil. This layer is part of the definition of an andosol - it must occur within the upper 15cm of the ground surface. So you should think of akadama as a soil, not a volcanic tephra deposit. It used to be many years ago, but that is mostly all gone now and replaced by clay minerals.

The alteration is interesting - with a lot of water, the ash breaks down to form allophane and imogolite, smectitic clay minerals that commonly occur together in an andosol. In fact, their occurrence is nearly diagnostic - andosols are pretty much the only kind of soil in which they are found. There is an interesting pH control on the allophane-imogolite association, however. As pH changes, aluminum can combine with humic acid that leaches from the surface forming Al-humus complexes that can substitute for the allophane-imogolite clay minerals. At a certain pH, one becomes dominant over the other. So in a typical andosol, horizons form as a response to changing pH in the subsurface. This is what I suspect the akadama-kanuma horizon is. Akadama is dominated by allophane-imogolte clay minerals with subsidiary Al-humus complexes whereas kanuma is dominated by Al-humus complexes with subsidiary clay minerals.

So to replicate the conditions in Japan, you need 1)volcanoes, 2)a lot of rainfall, 3) a lot of organics, and 4)time. About 50% of the andosols in the planet are in the tropics because of 2 and 3. But they can also occur in temperate areas where there is a lot of rainfall - areas like the Pacific NW. They're all over the place there.

Scott

 

[GroveKeeper]

I thought he was putting wood chips in the mix, and as a top dressing.

Wouldn't a top dressing of wood chips generate the algae, too?

It's easy to pull off the orchid miss and replace it.

I doubt the wood chips will form the same degree of algae. I have a big pile in my yard and algae hasn't formed on it. But that is the point of experimentation.

I suppose I could replace the moss every time it started getting slimey but that would be a waste of money and natural resources. Wood chips are free and I'm recyling.

 

[Vin]

Does pine bark qualify as wood chips?

 

[Adair M]

Akadama is a volcanic soil - it is comprised of partially to completely altered tephra deposits of volcanic ash and pumice. It's parent material was from arc volcanics, probably andesitic in composition like those in the Cascades. Remnant pumice grains are apparent in several bags I've bought, but generally the pumice and ash are nearly completely altered.

View attachment 97108

The pictures you may have seen of the akadama mined in Japan have layers - a dark organic-rich layer on top, then the red akadama layer, then the yellow kanuma layer. The boundaries between these layers are called soil horizons.

View attachment 97113

These kind of volcanic soils are called Andosols. An- is japanese for "dark" and -sol means soil. It refers to the dark, humic rich upper layer of the soil. This layer is part of the definition of an andosol - it must occur within the upper 15cm of the ground surface. So you should think of akadama as a soil, not a volcanic tephra deposit. It used to be many years ago, but that is mostly all gone now and replaced by clay minerals.

The alteration is interesting - with a lot of water, the ash breaks down to form allophane and imogolite, smectitic clay minerals that commonly occur together in an andosol. In fact, their occurrence is nearly diagnostic - andosols are pretty much the only kind of soil in which they are found. There is an interesting pH control on the allophane-imogolite association, however. As pH changes, aluminum can combine with humic acid that leaches from the surface forming Al-humus complexes that can substitute for the allophane-imogolite clay minerals. At a certain pH, one becomes dominant over the other. So in a typical andosol, horizons form as a response to changing pH in the subsurface. This is what I suspect the akadama-kanuma horizon is. Akadama is dominated by allophane-imogolte clay minerals with subsidiary Al-humus complexes whereas kanuma is dominated by Al-humus complexes with subsidiary clay minerals.

So to replicate the conditions in Japan, you need 1)volcanoes, 2)a lot of rainfall, 3) a lot of organics, and 4)time. About 50% of the andosols in the planet are in the tropics because of 2 and 3. But they can also occur in temperate areas where there is a lot of rainfall - areas like the Pacific NW. They're all over the place there.

Scott

I read all that. There are a lot of words that I have no clue as to what they mean. So...

Akadama, when it breaks down, still seems to maintain some degree of granularity. I suppose if left long enough it become solid. But I never let my trees go that long between repottings.

Perhaps my idea of "clay" is different than others. Here in Georgia, we have heavy red clay that is very dense.

 

[Adair M]

Says who?

My akadama clay pot.

Every person on the California coast makes sticky muck for rock planting from akadama.

I think you need to do some reading on just what clay is?????
View attachment 97110 View attachment 97111 View attachment 97112

Al, all the akadama I've ever seen is red. That looked more like wet kanuma to me. Kanuma, in my experience, is significantly softer than akadama.

The kanuma I use is almost white when dry, but a dirty yellow when wet.

 

[fredman]

Looking at the two akadama layers in the picture, the deeper layer will be more compacted and denser than the shallower layer. That to me suggests that the denser akadama at the bottom might well hold its structure better, than those of the top layer. Might it be that they mostly export the top layer, and keep the deeper layer for home use....?

 

[Shima]

Really the main difference would perhaps be the way in which the volcanic rock
originally crystalized. Pumice usually has more space within it's structure allowing
for more air. Which would support you argument.
Having said this... Would I or my plants actually know the difference ?
Not trying to argue or be insulting, just would wonder why then if the two
are so similar to each other... why not just eliminate one.

Exactly. It depends on the location of the volcano and the minerals present miles down during eruption. The cinder available to me holds much less H20 than pumice so I have no need for it. To say nothing of the polka-dot effect.

 

[wireme]

Does pine bark qualify as wood chips?

Sort of but not really, bark has a higher ratio of lignin to cellulose than wood and higher tannin content. This makes it slower to decompose, slower to decompose means a lower rate of nitrogen robbing. Maybe....I just made that up based on things that I think I know.

 

[Vin]

Sort of but not really, bark has a higher ratio of lignin to cellulose than wood and higher tannin content. This makes it slower to decompose, slower to decompose means a lower rate of nitrogen robbing. Maybe....I just made that up based on things that I think I know.

PHEW! I thought I was going to have a load of dead trees by the end of summer.

 

[sorce]

Bonsai Soil is a myth!

@fredman pumice Islands off your coast?

http://www.livescience.com/22268-huge-pumice-island-floats-in-pacific.html

Sorce

 

[Vin]

Bonsai Soil is a myth!

@fredman pumice Islands off your coast?

http://www.livescience.com/22268-huge-pumice-island-floats-in-pacific.html

Sorce

That ought to be enough pumice to keep all of us Nuts going for a while.

 

[sorce]

That ought to be enough pumice to keep all of us Nuts going for a while.

I hope Fredman got a big ass net!

Sorce

 

[fredman]

pumice Islands off your coast?

Please not MORE pumice. On some beaches I can fill a trailer on a afternoon beach ride ...

 

[Smoke]

I read all that. There are a lot of words that I have no clue as to what they mean. So...

Akadama, when it breaks down, still seems to maintain some degree of granularity. I suppose if left long enough it become solid. But I never let my trees go that long between repottings.

Perhaps my idea of "clay" is different than others. Here in Georgia, we have heavy red clay that is very dense.

Maybe instead of an idea, you should read some facts. Akadama is clay. Clay is just finely ground or decayed rock dust, be it volcanic ash or feldspar. The pot I made is from double red line akadama straight from the bag.

 

[Vin]

I hope Fredman got a big ass net!

Sorce

... and maybe a bigger boat?

 

[Smoke]

Sort of but not really, bark has a higher ratio of lignin to cellulose than wood and higher tannin content. This makes it slower to decompose, slower to decompose means a lower rate of nitrogen robbing. Maybe....I just made that up based on things that I think I know.

Actually you are correct. Fresh bark will not rob nitrogen and probably even if it did, most fertilize so often it would make no difference.