# Pumice versus perlite



## kiwi (Mar 15, 2014)

I have been using perlite in my growing media but was thinking about replacing it with perlite as I have a good source of pumice available to me. Does anyone use pumice instead or with perlite and if so what do you think of it a a component of a mix.


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## Trithor (Mar 16, 2014)

Is pumice not very rich in salt?


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## Ozpaph (Mar 16, 2014)

get some and soak in distilled water then measure tds and pH - that will help determine its suitability.
I once bought some catts growing in a volcanic rock (not pumice) they grew well.


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## gonewild (Mar 16, 2014)

Pumice is great! I have used it for decades. It does not soak up as much water as perlite. and does not crush and break down.


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## limuhead (Mar 18, 2014)

gonewild said:


> Pumice is great! I have used it for decades. It does not soak up as much water as perlite. and does not crush and break down.



Just out of curiosity, what color is the pumice? Over here we use what is called sponge rock, I thought it was perlite but maybe not. It is pretty hard, chunky and the large(1/2" to 3/4") tends to hold water more through capillary action than 'absorbing' it.


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## limuhead (Mar 18, 2014)

Never mind, just checked the label, it says 'Expanded Perlite'.


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## gonewild (Mar 18, 2014)

limuhead said:


> Just out of curiosity, what color is the pumice? Over here we use what is called sponge rock, I thought it was perlite but maybe not. It is pretty hard, chunky and the large(1/2" to 3/4") tends to hold water more through capillary action than 'absorbing' it.



Pumice is off white in color, a little gray. It is harder than perlite, difficult or impossible to crush between your fingers. It has somewhat of a closed air cell structure so it does not completely fill with water like perlite.


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## Stone (Mar 18, 2014)

From what I've heard, Kiwi pumice is very good. I wish it was cheaper and more available here. I would definitly use the larger grades for growing brachys ect. and catts too.


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## Chicago Chad (Mar 19, 2014)

Hey Fred- Sponge Rock has been a hassle for me to find in the states. Or if I do I have to buy a crate of the crap and I don't need that much. Fox farms 'Big and Chunky ' Perlite does not make it where I live very much either b/c there are far fewer cannabis growers here than Chicago. Do you have any suggestions? I like the stuff you guys use out there, although it does crush easily. I simply cannot find it.


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## Hera (Mar 19, 2014)

Did you try Roberts' Flower Supply? Should be cheap to ship.


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## Chicago Chad (Mar 19, 2014)

I have not Hera. Thanks for the heads up. I will have to get some Diatomite while I am at it. 2 birds with 1 stone- much appreciated!


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## SlipperFan (Mar 20, 2014)

Chicago Chad said:


> Hey Fred- Sponge Rock has been a hassle for me to find in the states. Or if I do I have to buy a crate of the crap and I don't need that much. Fox farms 'Big and Chunky ' Perlite does not make it where I live very much either b/c there are far fewer cannabis growers here than Chicago. Do you have any suggestions? I like the stuff you guys use out there, although it does crush easily. I simply cannot find it.



You might also try Grow Stones -- available from your local hydroponics store. It comes in a couple different sizes.


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## andre (Sep 19, 2014)

Love it. Use grow stones diatomous for all my Brachy's they love it. I don't have to change the media they like that. 


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## Chicago Chad (Sep 20, 2014)

An update:
Going back to this I have had excellent luck over the past year with a potting mix using grow stone, perlite, smaller pieces of sponge rock, small sized Orchiata bark and dolomite. The mix is very gravel-like in texture. Plants like delenatii, vietnamense, micranthum and armeniacum have all done very well. The thicker roots seem to push through it easily and are not stressed to the outside of the containers as has been discussed with Orchiata mixes.

And I found a local source for Sponge Rock so were making progress.


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## dodidoki (Sep 20, 2014)

kiwi said:


> I have been using perlite in my growing media but was thinking about replacing it with perlite as I have a good source of pumice available to me. Does anyone use pumice instead or with perlite and if so what do you think of it a a component of a mix.



I use it and I love it ( I mean plants love it). I use Akadama, it is pH natural lava granulates for bonsai trees, but slippers are growing very well in it.


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## Lmpgs (Sep 20, 2014)

dodidoki said:


> I use it and I love it ( I mean plants love it). I use Akadama, it is pH natural lava granulates for bonsai trees, but slippers are growing very well in it.



Where do you buy it from?


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## Parryaw (Sep 20, 2014)

I can only find perlite and they're really small! Would love to get my hands on some pumice 


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## dodidoki (Sep 20, 2014)

There is an orchid vendor in my country who sells this, another source is a Pet-Shop in my city and there can be found so called "Novasan", it is sold as substrate under cats ( heat treated neutral lava rock), it is same as akadama.


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## dodidoki (Sep 20, 2014)

For American growers:
http://en.wikipedia.org/wiki/Akadama


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## dodidoki (Sep 20, 2014)

For Europian growers:
http://www.fressnapf.de/shop/lava-streugut


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## Lmpgs (Sep 20, 2014)

dodidoki said:


> There is an orchid vendor in my country who sells this, another source is a Pet-Shop in my city and there can be found so called "Novasan", it is sold as substrate under cats ( heat treated neutral lava rock), it is same as akadama.



Thank you, I only find something similar 







What do you think? 

Once, I bought some phalaenopsis from an Ebayer (eco-sieben) and most plants were potted in a yellownish substrate, also I found the same at Popow's plants.


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## dodidoki (Sep 20, 2014)

I know two types of pumice: yellow Kanuma ( a little acidic, pH5,5, my plants didn't like it at all) and Kanuma ( pH neutral). What I use is not yellow, light brown. My experience that bigger granulates work better ( d is cca 6-10 mm) than smaller ( 3-5 mm).


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## dodidoki (Sep 20, 2014)

I show you this pic, you can see "my " Akadama.
https://imageshack.com/i/p8FCV4aLj


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