Akadama and watering

[Joe Dupre']

For those of you that use a high percentage akadama soil, how does the soil drain after a year or two or three? I've been re-reading Michael Hagedorn's book "Bonsai Heresy" and am curious how the center of the root ball that doesn't get replaced at repotting drains when the akadama breaks down into a solid mass. Intuition tells me that it may not drain well and would stay wetter, longer.

 

[Deep Sea Diver]

This is a very good question. I had this question when I read Michael Hagedorn’s book too.. and can only tell you what I’ve seen in the field.

We work with a whole lot of large to very large high quality trees/forests, almost all in some form of APL mix, repotting at least 20 to 40 a year. So I’ve seen a few root balls in the past three years. The media is rarely frozen due to enclosures, heat boxes etc.

From what I’ve seen the akadama in the root ball does as advertised. When repotting, the center of root ball does look like a big moist ball of clay filled with small particles of akadama mixed with pumice and lava. All the growing root tips which absorb water and nutrients tend to be outside this area. The roots under the trunk tend to be lignified support structures for the root tips. I’m actually not sure how oxygen percolates into this area, but water does, so oxygen can too. This area is not anoxic however, which surprised me a lot.

The surface area of the media gets clogged up over time due to dirt falling from the sky, broken down moss etc. If this top layer is not removed and replaced when needed, water will take longer and longer to percolate down to the media where the interstitial spaces are intact and the area is free flowing.

I suspect…. and could be wrong, that some of the complaints of folks trying out akadama, besides that it can be pricey, or have acquired low quality product, that at least some are caused by not properly servicing this layer.

I’ve heard freezing can do this to some forms of akadama, yet my own trees with APL mix that freeze haven’t shown this. Possibly because of the more moderate weather in Puget Sound. We still get multi day freezes here where the rootball is frozen solid for a week and a half or so. Maybe someone more knowledgeable that has multiple trees in APL mix in a colder growing zone could chime in here about that facet?

Shifting gears a little.… I have seen the ‘Shin’ of old satsukis planted in 100% Kanuma not properly percolate over many years.. Kanuma has the same properties as Akadama, yet is softer due to being the more metamorphosed layer immediately under akadama. That’s the reason some folks are shifting to a 90/10 Kanuma/pumice mix, to keep the media more friable.

I hope that helps!

Cheersï
DSD sends

 

[Joe Dupre']

Thanks, Deep Sea Diver. Real, hands-on experience is what I was looking for. There is only one person I know in the that has started to use akadama, albeit in the neighborhood of 15-20%. She says she has seen an obvious improvement in most of her trees. I went to visit her garden and was simply amazed! Not state-class......not national-class ......but world-class trees. 8" Japanese black pines , 12" trident maples and 15" bald cypress. I may look into adding akadama to my soil mix.

 

[Deep Sea Diver]

Thanks, Deep Sea Diver. Real, hands-on experience is what I was looking for. There is only one person I know in the that has started to use akadama, albeit in the neighborhood of 15-20%. She says she has seen an obvious improvement in most of her trees. I went to visit her garden and was simply amazed! Not state-class......not national-class ......but world-class trees. 8" Japanese black pines , 12" trident maples and 15" bald cypress. I may look into adding akadama to my soil mix.

You are welcome @Joe Dupre'

Actually I was just watching Ryan Neal repot a cascade Mountain Hemlock in a 3:1:1 APL mix, which he uses for all his elongating species (definately not the same ratio in other species ). Ryan's talk track includes the reasoning that other medias will definately grow trees.... and akadama won't necessarily grow the biggest trees.....

....Yet only akadama in the media has proven so far to create a finely refined, scaling root mass that reflects itself in the tree/branch structure by producing finely ramified branching.

Where I volunteer we all take care of 150 incredible museum quality trees. I can say absolutely state without a doubt that the APL mix, in fact does accomplish this, given other variables, maintenance, watering, fertilization, insects, diseases, fixing surface porosity, winter care/storage etc. etc. are properly attended to.

Cheers
DSD sends

 

[vp999]

I think Mach5 uses 100% Akadama on all his maples and others as well if im not mistaking. We all know what his maples look like....

 

[Joe Dupre']

If the akadama root ball is so dense, does it follow that it takes longer to dry out and might need watering less frequently than, say a pumice/lava mix?

 

[Deep Sea Diver]

Wow! Really Interesting question….

You know in bonsai the answer is always “It depends… but I’ll hazard sort of a reply….. no mention of percentages in your proposed media. I’ll go with 50/50 then. (I’ll be upfront now in saying I do not have a lot of experience with pumice/lava media… only in some limited propagation scenarios.)

Yet I would have to say yes, but maybe not.

Yes , it’s highly likely as even with a 50/50 pumice lava media one would have a lot less water holding capacity then in a 33/33/33 APL. media, not to mention a 3:1:1 APL media. ( APL = Akadama Pumice Lava for readers not conversant with the acronym).

Actually if one would use Andrew Robson’s maple media it would be 50/50 Akadama/Pumice!

Maybe not … because of akadama’s root scaling properties. Which would create a greater root surface area to uptake water and nutrients… which it would need to support a greater root mass and fine branching. Maybe even needing more water…And as often?

So…. Yes likely , but not sure if it would be quantifiable. It would be cool to design an experiment answering this question.

Love to hear other’s opinions and rationale on this point!

cheers
DSD sends

 

[MrFancyPlants]

You are welcome @Joe Dupre'

Actually I was just watching Ryan Neal repot a cascade Mountain Hemlock in a 3:1:1 APL mix, which he uses for all his elongating species (definately not the same ratio in other species ). Ryan's talk track includes the reasoning that other medias will definately grow trees.... and akadama won't necessarily grow the biggest trees.....

....Yet only akadama in the media has proven so far to create a finely refined, scaling root mass that reflects itself in the tree/branch structure by producing finely ramified branching.

Where I volunteer we all take care of 150 incredible museum quality trees. I can say absolutely state without a doubt that the APL mix, in fact does accomplish this, given other variables, maintenance, watering, fertilization, insects, diseases, fixing surface porosity, winter care/storage etc. etc. are properly attended to.

Cheers
DSD sends

Interesting to hear about the elusive care regimen for elongating species. I have a couple Eastern Hemlock and I have read that they prefer a bump up in the organic, so I have been doing 1/3’s APL + ~10% 50/50 spaghnum and compost. I don’t know if the original poster would consider that high percentage, but they seem to like it without repotting in to the 5+ Year timeframe with hard freezes and without skipping a beat. I load up the high nitrogen fertilizer too, w Agriform fertilizer tabs.
We’ll see how the repot into the Rayner pot goes this spring.

 

[Wires_Guy_wires]

I think a good shin is like a pocket of field soil; it doesn't take up a whole lot of water if the medium around it is free draining. In the case of field soil, this can be problematic. In the case of akadama, this could be beneficial because clay sticks to itself and acts as a wick for water. It's not as water repellent as forest dandruff or potting soil. Maybe akadama shins are perfect at finding that water/air balance that way.
I have no certain way of telling because we have 30-60 freeze thaw cycles a year with insane rains in between; it's mush in a year, making it unsuited for conifers in my climate.

 

[leatherback]

No akadama

 

[August44]

This is a very good question. I had this question when I read Michael Hagedorn’s book too.. and can only tell you what I’ve seen in the field.

We work with a whole lot of large to very large high quality trees/forests, almost all in some form of APL mix, repotting at least 20 to 40 a year. So I’ve seen a few root balls in the past three years. The media is rarely frozen due to enclosures, heat boxes etc.

From what I’ve seen the akadama in the root ball does as advertised. When repotting, the center of root ball does look like a big moist ball of clay filled with small particles of akadama mixed with pumice and lava. All the growing root tips which absorb water and nutrients tend to be outside this area. The roots under the trunk tend to be lignified support structures for the root tips. I’m actually not sure how oxygen percolates into this area, but water does, so oxygen can too. This area is not anoxic however, which surprised me a lot.

The surface area of the media gets clogged up over time due to dirt falling from the sky, broken down moss etc. If this top layer is not removed and replaced when needed, water will take longer and longer to percolate down to the media where the interstitial spaces are intact and the area is free flowing.

I suspect…. and could be wrong, that some of the complaints of folks trying out akadama, besides that it can be pricey, or have acquired low quality product, that at least some are caused by not properly servicing this layer.

I’ve heard freezing can do this to some forms of akadama, yet my own trees with APL mix that freeze haven’t shown this. Possibly because of the more moderate weather in Puget Sound. We still get multi day freezes here where the rootball is frozen solid for a week and a half or so. Maybe someone more knowledgeable that has multiple trees in APL mix in a colder growing zone could chime in here about that facet?

Shifting gears a little.… I have seen the ‘Shin’ of old satsukis planted in 100% Kanuma not properly percolate over many years.. Kanuma has the same properties as Akadama, yet is softer due to being the more metamorphosed layer immediately under akadama. That’s the reason some folks are shifting to a 90/10 Kanuma/pumice mix, to keep the media more friable.

I hope that helps!

Cheersï
DSD sends

Does "APL" stand for apples, peanuts and lettuce?

 

[Maiden69]

I think Mach5 uses 100% Akadama on all his maples and others as well if im not mistaking. We all know what his maples look like....

So does Ryan on all his deciduous trees.

 

[leatherback]

APL" stand for apples, peanuts and lettuce?

Nope.

Kakadama
pulverized Pumice
Lofty Lava