# Kanuma



## dodidoki (May 5, 2012)

Anyone heard about this? Has anyone experience with this? Mr. Popow said that he has very good results with this yellowish sponge like stone.


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## KyushuCalanthe (May 5, 2012)

dodidoki said:


> Anyone heard about this? Has anyone experience with this? Mr. Popow said that he has very good results with this yellowish sponge like stone.



It is a very common material here in Japan and cheap. I find it to be excellent for some plants and less so for others. The reaction is on the acidic side so it is favored for growing azaleas, rhodos, and other acid loving species. The airy texture allows for excellent fine root growth for acid loving shrubs in particular. Mixed evenly with peat moss it one can create the perfect compost for just about any fern. It can also be mixed with other substrates such as pumice or other Japanese "soils" like akadama and kiryu.

I've used it for various terrestrial orchids, either pure or mixed, with good results. For fun I've planted a few Paphs in it and the seem to do pretty darn good. It is excellent for growing Jenosa type Cymbids, such as C. goeringii, though I like to mix it with other materials rather than use it pure.

Other than the acidic reaction, its one short coming is that it tends to dry excessively, so one has to be careful not to let the pot dry out. Having said that, once dry it easily reabsorbs water rather than repel it. 

An all around excellent potting material.


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## jokerpass (Apr 7, 2020)

Yes, Kanuma (鹿沼土）is very good for terrestrial orchids especially for all Asian Cymbidiums (東洋蘭). Yes, for Cymbidium goeringii, I buy premixed bag with 3 types of pumice, hard kanuma （硬質鹿沼土）, baked/fired akadama (焼き赤玉土), and satsuma (薩摩土) from Japan.


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## NYEric (Apr 7, 2020)

Yes it is. I got a little, cant remember from whom, and my ponerorchis are doing great in it.


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## richgarrison (Apr 17, 2020)

how does that compare to akadama? and does it decompose over time, or is it relatively inert?


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## Ray (Apr 18, 2020)

The mineralogy may be different, but kanuma is a fired soil product, so akin to LECA and should not crumble over time.

Akadama is a dried clay, so may crumble over time. The pH may affect the rate of that.


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## Linus_Cello (Apr 18, 2020)

Try a store or website that specializes in bonsai to find either product


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## NYEric (Apr 18, 2020)

Not in NYC!


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## Linus_Cello (Apr 18, 2020)

https://www.kusamonogardens.com/soil


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## richgarrison (Apr 19, 2020)

Awesome guys thanx much... the distinctions between the 'fired clay' versus 'dried clay' was what i needed.... I have a bonsai supply within minutes of my visit to main street...


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## Dew (Apr 23, 2020)

Ray said:


> The mineralogy may be different, but kanuma is a fired soil product, so akin to LECA and should not crumble over time.
> 
> Akadama is a dried clay, so may crumble over time. The pH may affect the rate of that.



It’s actually very soft pumice, not fired soil. It contains much more water than normal pumice. You may be talking about Yaki Akadama, which is fired Akadama soil and doesn’t really crumble.

I’ve recently visited a nursery that specialises in paph in Japan, and the owner said Kanuma works pretty well for Micranthum and Armeniacum. But it’s recommended to repot annually since it does crumble. 
I don’t have enough experience to comment on this, but this is what he said.

p.s. Sorry for my English **


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## jokerpass (Apr 23, 2020)

Hi Drew: This is what I understand from the 3 pumices (Kanuma, Akadama, and Satsuma). Mind you that there are also different qualities of the pumices.

Kanuma tsuchi （鹿沼土): regular kanuma, whitish brown looking. It is very soft, and absorbs the most water out of the 3 pumices.
Koushitsu Kanuma tsuchi (硬質鹿沼土）: hard kanuma. It is treated wit high temp. Makes Kanuma harder and less likely to crumble. This is better quality Kanuma and it is much better for C. goeringii

Akadama tsuchi (赤玉土): regular Akadama, reddish brown looking. It is very soft, and has the most acidic pH out of the 3 pumices.
Yaki Akadama tsuchi (焼き赤玉土): baked, fired treated Akadama. It is treated with high temp. Makes akadama harder and less likely to crumble. This is better quality akadma and it is much better for C. goeringii.

Satsuma tsuchi (薩摩土・さつま土): whitish looking. It is hard. It has the poorest water rentention out of the 3 pumices. However, it is the most porous so it provides the aeration for C. goeringii's root system. 

Lastly, there is another type of pumice called Karu-ishi(軽石): this is very light pumice and can be used and added into the C. goeringii potting mix if desire. This is volcanic in origin and it is very porous so good for the roots and drainage for C. goeringii.


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## Dew (Apr 23, 2020)

Hi jokerpass! Your description sounds pretty accurate. Except that Akadama is not pumice, it’s made of clay-ish soil actually. But the property is as you described 

Speaking of goeringii, my uncle owns a small goeringii nursery, and he said Hyuga Tsuchi (日向土) works great for goenrigii. He use just pure Hyuga for all his goeringii.
It is another kind of pumice, the property is somewhere between Karuishi and Kanuma. Also, Ezo Suna (蝦夷砂) is basically the same thing as Hyuga.


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## jokerpass (Apr 23, 2020)

Hi Dew:

I believe the the hard Kanuma (硬質鹿沼土) has very similar properties Hyuga Tsuchi (日向土). I think that Kyuga tsuchi is even better quality than kard kanuma. Yes, it is very good for C. goeringii. I have never used Ezo suna (蝦夷砂) .

What is the name of your uncle's C. goeringii nursery? I am finally able to import Japanese C. goeringii (日本春蘭) from Japan recently. Perhaps, I can get in touch with you uncle. Does your uncle belong to 日本伝統園芸協会？


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## Dew (Apr 24, 2020)

He started his nursery after his retirement from a rice breeding institution as an extension of his hobby. So it’s pretty small, and I doubt he belongs to 日本伝統園芸協会...


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## jokerpass (Apr 24, 2020)

Thank you Dew.


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