Kiryu Soil

[Thomas J.]

Just wondering how this stuff (Kiryu Soil) would work in place of Akadama for JBPs since I can't find any really hard fired Akadama like I used to, seems the stuff out there now is the kind that breaks down and turns into mud. Thought I would replace it with this or at least try. Some say It's pretty acidic, just wondering what others think who have used this.

 

[NeedlesAndLeaves]

I use Kiryu mixed in with my substrate for pines and junipers. It is a bit more accidic.
It has the capacity to hold nutrients but holds little to no water.
So not really a substitution for akadama.
Mixed in works quit well for me.

 

[Juanmi]

I've always used it mixed with akadama (70/30 is the recommended)

Indeed, it is a bit acidic.

Akadama here went a bit pricey, so I started experimenting with soil. At the moment I'm usin a volcanic + organic + zeolite mix and it works fine for me.

Akadama is good, but there are plenty of substitutes. They use it on Japan because it is cheap and available. Actually, they are pretty shocked that we use it on the west

 

[stewarjm192]

I went down the rabbit hole a few weeks ago and asked many different soil suppliers, as well as some professionals what they thought. The consensus was that it was closest to pumice in terms of the three traditional aggregates we use. comparing it to pumice, it holds a little less water, has a slightly harder and more durable particle(IE: breaks down slower), and is slightly more acidic. The biggest factor will be cost. Michael Hagedorn recommended, as did John Romano, if you have it, use it, its good, but pumice is more affordable, and Kiryu does not have any major benefits over it. Pumice(US sourced) even has some benefit over Kiryu, depending on the application

 

[Maiden69]

Kiryu is usually refered to as Japanese pumice but they are not so similar. The main difference between kiryu and pumice is that pumice will not breakdown and kiryu as well as akadama will in time. Taisho-en in Japan is one of the nurseries that uses kiryu in their mix extensively. They do 70/30 akadama/kiryu, I have used that ratio with good results. I have only seen one experiment where it was compared to other substrates and kiryu/akadama performed better than pumice/akadama mix at the same ratio. Another member that uses kiryu in his mix is @MACH5. I think he is doing around 90/10 if I remember correctly. Right now it is not as easy to find as a few years back, I used to order from Jonas but he has been sold out a few times this year.

comparing it to pumice, it holds a little less water, has a slightly harder and more durable particle

Completely different from my experience. I feel that it holds more water and it definitely breaks into dust like pumice when I crush it with my fingers.

This is big particle kiryu that I was using as a top dressing, it holds water for a long time and turns kinda orange, when it changes from orange to this color I knew it was time to water the trees.

 

[River's Edge]

Just wondering how this stuff (Kiryu Soil) would work in place of Akadama for JBPs since I can't find any really hard fired Akadama like I used to, seems the stuff out there now is the kind that breaks down and turns into mud. Thought I would replace it with this or at least try. Some say It's pretty acidic, just wondering what others think who have used this.

Kyru is softer and breaks down more easily than most Akadama, as well as more on the acidic side. I find it most useful for Azalea and other acid loving plants with very fine feeder roots. Also useful for rock plantings, slab and muck wall as one of the components. Definitely not a substitute for hard Akadama in my experience.

 

[Glaucus]

Not a geologist or an inorganic chemist, but isn't the thing with pumice that it doesn't chemically describe the type of rock? But only a process that the rock underwent? Namely that it was ejected from a volcano under pressure, creating the air bubbles/pockets? Which means that if something is pumice or not has nothing to do with the type of rock it is. Though it is very likely to be some type of extrusive igneous rock. Which would mean that the specific properties of a pumice would depend on the specific volcano, or even the specific eruption event, if one volcano had many. Akadama I believe all comes from one volcanic eruption. Not sure if Kiryu all comes from the same spot. But it could mean that there are forms of pumice that are both either harder and softer than kiryu.

 

[yenling83]

Agree with the first three replies above. A few important points. Kiryu is not a good replacement for Akadama because it's quite different than Akadama. It would be a great addition to mix in with Akadama, but pumice is a much cheaper alternative that works possibly slightly better. Akadama is heat treated, but not baked. We actually do want Akadama to break down over time and scale as our fine roots increase in numbers. Cheap quality Akadama will break down too fast, while good quality will break down more slowly and is harder. You can also get too hard-fired Akadama where the particles will not break down over time-which is not what you don't want. If the Akadama is fired and too hard, the clay particle looses the beneficial aspects and you might as well just use all pumice. With all these soil products it's extremely important to sift out the fine particles before using and to learn to water to achieve the appropriate balance of water and oxygen.

 

[Juanmi]

Taisho-en in Japan is one of the nurseries that uses kiryu in their mix extensively. They do 70/30 akadama/kiryu, I have used that ratio with good results.

There is a spanish youtuber that went to Taisho-en for a few weeks (in 2 occasions), and he always uses 70/30 Akadama Kiryuzuna.
So most spanish speakers bonsai enthusiasts know about that.

 

[NeedlesAndLeaves]

A Kiryu product discription. Source: bonsaiplaza.com

 

[Maiden69]

There is a spanish youtuber that went to Taisho-en for a few weeks (in 2 occasions), and he always uses 70/30 Akadama Kiryuzuna.
So most spanish speakers bonsai enthusiasts know about that.

He's the one that did the test that I mentioned. David Cortizas. He joined all his videos under Kaeru-en, he's been to Taisho-en more than twice now, that's the nursery of Taiga Urushibata's father. I think Sergio has been there as well, or at least there is a mention of Taisho-en on his website.

Kaeru-En 蛙園

Que el bonsai es difícil es una leyenda, ahora en Kaeru-En 蛙園 encontrarás la respuesta a todas tus preguntas. Un abrazo.... y hasta el próximo vídeo!!!.

www.youtube.com

 

[Wires_Guy_wires]

Not a geologist or an inorganic chemist, but isn't the thing with pumice that it doesn't chemically describe the type of rock? But only a process that the rock underwent? Namely that it was ejected from a volcano under pressure, creating the air bubbles/pockets? Which means that if something is pumice or not has nothing to do with the type of rock it is. Though it is very likely to be some type of extrusive igneous rock. Which would mean that the specific properties of a pumice would depend on the specific volcano, or even the specific eruption event, if one volcano had many. Akadama I believe all comes from one volcanic eruption. Not sure if Kiryu all comes from the same spot. But it could mean that there are forms of pumice that are both either harder and softer than kiryu.

I think the composition of pumice is more or less similar, independant of geology or location.
Same goes for perlite.
I think this has to do with the minerals and the conditions that allow it to form. Sure, per location it might contain more of something like fluoride, iron or boron, but I think the silicates and main constituents are nearly identical whether it's Italian or Australian. But I can very well be wrong.

Akadama is clay soil found on top of volcanic soil, the water boiling is what makes it so porous. At least, that's what I've been told.

 

[Glaucus]

The composition of pumice wouldn't be similar. But for horticulture, the actual mineralogy may not matter too much. Apparently, they are first made up of a type of rock, which says what combination of minerals are actually inside.

Akadame is not a soil or a pumice. It is volcanic ash and dust that has sedimented into a clay rock. And once sedimented, was eroded further by rain. And that after forming a clay rock, the minerals actually change to allophane and imogolite. As these are formed by either weathering or metasomatism. Making it a metamorphic rock.

I have seen kiryuzana being referred to as sand. Apparently, it is sand from the Kiryu region, 桐生砂, the zuna part meaning 'sand'. And it coming from Gunma Prefecture.

Looking at some Japanese site descriptions, this one seems to be pretty much the consensus:

"Kiryu sand is volcanic gravel that is produced from a layer even lower than Kanuma soil, and is mountain sand produced around Kiryu City in the Akagi Mountains in Gunma Prefecture. Kiryu sand is harder and more angular than Kanuma soil, and has excellent breathability and drainage, so it is mainly used for plants that do not like excessive moisture. It is often used for bonsai such as pine and cypress bonsai, so it is a must-have soil for those who want to grow pine bonsai. It is also often used for wild plants, and may be used alone for perennial plants.It contains a lot of iron, so it is reddish yellow-brown and slightly acidic. It contains a lot of iron, but it is clean and does not contain fertilizer. The grains are strong and do not break down even with repeated watering, so it can withstand long-term use. It is truly ideal as a basic soil for bonsai. However, Kiryu sand alone drains too well, so it is often mixed with Akadama soil. In addition to bonsai, this soil is also widely used for oriental orchids, omoto, wild plants, succulents, etc."

Not sure if they mean it is actually below the kanuma layer. Is there kanuma in the ground all across Japan? So they have kanuma in Kiryu city and kiryu in Kanuma city? But they dig one up ine one spot, not the other?

And would it be very similar to most types of lava one can buy? Often, lava is red as well, which is I assume also because of iron ixide. And it is also harder and much more dense than akadama.

 

[damiano68]

Kyru è più morbido e si rompe più facilmente della maggior parte degli Akadama, oltre ad essere più acido. Lo trovo molto utile per l'azalea e altre piante acidofile con radici nutrici molto sottili. Utile anche per piantagioni di rocce, lastre e mucchi di fango come uno dei componenti. Sicuramente non è un sostituto dell'Akadama duro, secondo la mia esperienza.

Ciao, forse ti confondi con kanuma?

 

[MACH5]

Kiryu is very similar to pumice. It does not break down and holds its structure unlike akadama. It is more acidic which is perfect for many deciduous species including maples. I have been using a mix of 75% akadama with the rest being Kiryu for almost 30 years with great success. I also like it for its aesthetic value. When damp it's similar in color to akadama. Pumice is white and always looks like aquarium gravel to me. I use it too but only on trees in development since it's cheaper as well.

You must adjust your mix ratio depending on your location.

 

[River's Edge]

Ciao, forse ti confondi con kanuma?

Exactement, my bad

 

[Maiden69]

It does not break down and holds its structure

Which brand do you use? I have used the one that Jonas sells and this one from Amazon and they break down for me. Not as fast as akadama, but they do scale down.

Amazon.com

Jonas kiryu

Kiryu

Kiryu is a pumice-like volcanic particle for acid-loving plants. It's a common ingredient in bonsai mixes. Volume: 13 liters (3.4 gallons) Weight - Small: 17.5 lbs., Medium: 15.9 lbs. Learn more about discounts for bulk orders here. Read our Soil FAQ.

store.bonsaitonight.com

 

[Glaucus]

Maybe kiryu is a form of scoria then? Bit confusing how it is associated with rivers or said to be sand, if it is rock dug up from quite deep.

 

[INDIGO-STEVE]

Some Kiryu is high fired and others isn't. That's why some break down and others don't.

 

[johnl445]

How is the quality of Kiryu that is used in Aoki blend?