Please advise on pumice

Rivian

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I am in the market for a big bag (1000L) of pumice but I dont know what type is best
I also dont know if azalea roots can penetrate pumice like Kanuma, in which case I could pick the larger grain. I would guess they can not. I think most other species can, though?

There is washed and unwashed pumice, and the possible grains are 1-5, 2-4, 2-5, 4-8 mm
Ideally I would have liked 3-6 mm but there is none

pH is 6,5 all

The 1-5 mm has a mix with lava available. I'm not sure what the value added by the lava is, maybe iron? It doesnt say but it might be a 50/50 mix

The mix is the most expensive at 330EUR and the cheapest is the unwashed 4-8 mm pumice at 280EUR

Most of my plants are ~3 years old, but I also have a tendency to rarely pick up huge taxus. How bad is it to plant a 3 man tree into 2-4 mm pumice?

Help me pick, please
 

Wires_Guy_wires

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I use 2-5mm pumice for everything, except when I'm using vulkastrat.
But I found that the heavy weight pumice is performing better than the lightweight stuff. Not sure where the difference comes from, maybe source related or something. I got mine from a german amazon seller.
 

Rivian

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I use 2-5mm pumice for everything, except when I'm using vulkastrat.
But I found that the heavy weight pumice is performing better than the lightweight stuff. Not sure where the difference comes from, maybe source related or something. I got mine from a german amazon seller.
Ive found Amazon to generally be more expensive than other options. I'm curious what you payed tho

We have probably looked at similar companies, Ive checked Rotopor, Interbims and Vulcatec. Prices for unwashed pumice are comparable.
Actually its not mined super far from where I live but not close enough so that going there and buying in person is more convenient.
But its cool we have this stuff in the soils, I much prefer this to importing. 3,6 cubic kilometers pumice I think. Wonder how long that will last

In the washing process the heavy pumice is discarded along with the impurities (perhaps depending on the company, to varying degrees)
Maybe the heavy stuff has some more characteristics of lava that benefit you, or its the impurities that provide nutrition

I think I will probably use the pumice lava mix. This will be my main soil component and in just pumice some trees will get blown over easily, I reckon.
 
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3,6 cubic kilometers pumice I think. Wonder how long that will last

I think 3.6 km^3 would last us all a lifetime. 3.6 m^3, on the other hand, well...it depends. A year ago, I repotted about 20-30 bonsai and pre-bonsai with about half as much, using it for about 1/3 of my mix. Not that that means all that much.
 

Glaucus

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[edit]
Actually, the link I found on amazon seemed more like crushed rock than pumice.
And then I figured out I don't actually have anything informative to contribute.
If someone finds some good and cheap product, I'll also give it a try for growing nonbonsai potted azaleas.
 
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Rivian

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[edit]
Actually, the link I found on amazon seemed more like crushed rock than pumice.
And then I figured out I don't actually have anything informative to contribute.
If someone finds some good and cheap product, I'll also give it a try for growing nonbonsai potted azaleas.
I have looked at lots of substrates lately, if you tell me what grain, quantity and characteristics it should have I might be able to give you a pointer
 

KiwiPlantGuy

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Hi,
My substrates of choice are Pumice, Zeolite, Bark, and Lava all within the 2-5mm grades (all sieved and if remembered to wash also).
But for growing out in large pots etc, I use either straight composted bark, or a small addition of used pumice.
I know of at least one bonsai grower who grows everything in Pumice and Zeolite and her plants always look amazing.
Your choice I guess,
Charles
 

Mike Corazzi

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Pumice has ....rescued....several trees for me. I guess I'm too dumb to draw a logical conclusion from that.

:eek:
 

Rivian

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There is also an option with zeolite
basically the premium stuff whereas just pumice + lava is standard
but..
I dont trust zeolite
I dont know if it could build up salts or whatever Ive read
Now kiwiplantguy mentioned a person using it but I can also find dozens of people endorsing turface..
Im curious what the professionals think about zeolite, I think Ryan was asked during the soil stream but mostly withheld judgement
 

Maiden69

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I also dont know if azalea roots can penetrate pumice like Kanuma,
This is a no... I don't see anyone else reply on it. Pumice is hard, like a stone hard but porous.
1-5, 2-4, 2-5, 4-8 mm
From those sizes I would get the 4-8mm, as the other ones are in the too small category. But since you say your plants are mostly 3 yr old, 2-5mm will work as well, but would be in the shohin tree size.

I think the 4-8mm could bring some smaller pieces as well, or you could crush a few in the event you need to pot a smaller tree. I do this with my pumice when I need is smaller than the 1/4 to 3/8" size I use to order (6-9mm). I can get the same amount for $212 now, but shipping to me is over $300. I may have to bite the bullet and order it since there is no other option close to my home.
 
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