Do any of you keep your trees in 100% pumice?

[Johnathan]

You gotta glue 8-12 pieces of DE around a piece of pumice!

More driveway fun!

Sorce

Lol trying to find a happy balance for these JBP! The deciduous prefer 100% DE, and so does my wallet

 

[sorce]

Lol trying to find a happy balance for these JBP! The deciduous prefer 100% DE, and so does my wallet

Its only one instance, but my JBP seedling grew like crap in Pumice, great in fine DE, ok in big DE.

I think you're right on with a mix of pumice and de, since DE alone is eventually too wet, at least with my watering habits and climate.

Sorce

 

[Shima]

When I did that I use to put small pebbles (or something similar) on top of the sphagnum because it dried so quickly. The moss don't wet easy when it is dry.

Water goes right through "my" moss.

 

[fredman]

Water goes right through "my" moss.

I haven't done it for a while... Maybe I over reacted then..will see. I imagine when the top dries, the bottom still stays damp for a while. I wonder if different moss reacts different to...?
Anyway...i'm doing it again this year and i'll keep a closer eye.

 

[Shima]

I haven't done it for a while... Maybe I over reacted then..will see. I imagine when the top dries, the bottom still stays damp for a while. I wonder if different moss reacts different to...?
Anyway...i'm doing it again this year and i'll keep a closer eye.

There does seem to be a difference in sphagnum depending on where it's from and how it's handled. I used to buy bales of quality moss from NZ, I think, but now, what's growing here works best for me. I have no idea why I actually bought moss when I live in a bleeding rain forest with moss everywhere. I dry it in the sun under cover and rub it through 1/4 " screen, or better yet, run it through a food processor. But that takes a long time.

 

[fredman]

LoL you have a point there. I live in NZ and buy the stuff from the hardware store. I should get out more, and go find my own

 

[NamesakE]

@bonsaichile fellow Coloradoan here! Do you get it locally? I would def use it if it was available at a hardware or landscape store but just cant find it.

I use this place (I'm not affiliated with them in any way I just like their stuff) and their pumice is pretty good. Generalpumiceproducts.com You have to rinse the hell out of it though!

 

[Deep Sea Diver]

IMHO Kiwi sphagnum has been shown to superior than most others for use in our orchids and azaleas then most others, yet I’m sure there are other recipes that would do fine. In fact my wife is experimenting with adding ‘plastic peanuts’ to her orchid mixes instead of clay shards.

For some variety of reasons every time I ask a question about things like “Is pumice the best media for bonsai?” I always get the answer, “It depends....”.

John Muth, at the now closed Bonsai NW store, swore pure pumice in an Anderson flat would help just about any pine in trouble put out plentiful roots and new growth in a year, or so.

As someone said earlier Michael Hagedorn, wrote a nice couple really chapters on media, including the benefits of using akadama and other organics in a mix, their impact on ramification and on why the media composition needs to evolve as trees mature it depends”

At the PB museum, where we work with high grade trees, we mostly use either Boon mix (or straight kanuma for azaleas). Yet @Walter Pall related on youtube he wouldn't touch akadama in his garden media, preferring a straight inorganic mix.

I learned a lot from @markyscott in his resources and threads about media followed by a number of discussions and more with added practice. The upshot of all this information seemed to me to be about media “Its gotta flow and drain, It’s gotta hold then give off water and nutrients over time, and it all depends on the particular tree and situation.... and oh yes a beautiful pot with poor drainage can ruin the effect of a good media.“ I’d recommend both the @markscott resource and a good read of his threads if you haven’t.

Along the line I found this data table in a @markyscott thread on CEC, which I will resurrect to add to the information here. After I-read this I realized another reason why charcoal is in Boon’s mix.

cheers

DSD sends

 

[Ben in Kzoo]

The kanuma PH is surprising!
The CEC of Akadama is disappointing

 

[Cajunrider]

If not, why not? The small (not "fine") pumice coaxes roots out of air layers.
It serves well as an ICU for ailing trees. (got one recovering in it now)
It doesn't break down like akadama.
I retains a good amount of moisture without being "wet."
It breathes well.

So, if it isn't a perfect "soil" why not?

Can't afford it around here.

 

[PaulH]

I almost always put newly collected trees in pure pumice but transition to standard A P L mix after they are established.

 

[Deep Sea Diver]

The kanuma PH is surprising!
The CEC of Akadama is disappointing

Both kanuma and Akadama are volcanic products, Hence the low pH. Akadama is in the layer above kanuma, hence more weathered, which has muted its properties.

Not sure I understand why the CEC so disappointing…. It’s actually very high for a media that isn’t organic or formerly organic. Organic materials shine more for their addition of carbon etc to the rhizosphere, adding feedstock and building the microbial community.

CEC isn’t everything in a media, nor is pH. Akadama (and kanuma) are both more important root scaling properties secondary for their CEC.

Can't afford it around here.

Check out the Soil Properties of soils resource by @markyscott at the end he has a cost comparison of many media used in Bonsai after sifting. It’s revealing.

Given you properly recycle and reuse akadama (about 60-75% in my many trials) it becomes even very inexpensive. (Kanuma recycles too, but I need more data… seems like about the same.) As does lava and pumice which recycle at about 95%.

That’s the bigger picture on these media

Cheers
DSD sends

 

[Wood]

Given you properly recycle and reuse akadama

Do you do anything to help contain soil pathogens? Some of the pros I have worked with recommended against reusing soil for that reason

 

[Deep Sea Diver]

It takes extra work that only a hobbyist might want to do. Both @leatherback and I have sightly different techniques. See his website here.

We do some extra steps as we have a wetter climate and some of the used media I recycle comes from different sources. Usually do about 15-20 gallons a year, sometimes way more..

For non azalea media.

• Basically collect until there is enough to batch.
• Water wash in a wheelbarrow, pour into an about 1/8” large sieve.
• Rinse through the sieve & drain.
• Dig out heavier remnants and sieve these.
• Put into large baking pans.
• Heat to 425F for 90mins (might need range hood on full if bark is in the mix - I usually do this when my better half is out.
• Sieve and add add’l akadama as needed to different bonsai mixes.

It may be overkill, but then again, I absolutely never have pathogen media issues whatsoever.
DSD’s
.

Mixed in the bucket after sieving. Usually add Biochar before a repot.



I figure I’ve saved an awful lot of money I can use for other things bonsai this way. For example I just purchased this Rocky Mountain Bristlecone with some of the money I saved from the past batches.



Good luck!
DSD sends

 

[markyscott]

Both kanuma and Akadama are volcanic products, Hence the low pH. Akadama is in the layer above kanuma, hence more weathered, which has muted its properties.

Not sure I understand why the CEC so disappointing…. It’s actually very high for a media that isn’t organic or formerly organic. Organic materials shine more for their addition of carbon etc to the rhizosphere, adding feedstock and building the microbial community.

CEC isn’t everything in a media, nor is pH. Akadama (and kanuma) are both more important root scaling properties secondary for their CEC.


Check out the Soil Properties of soils resource by @markyscott at the end he has a cost comparison of many media used in Bonsai after sifting. It’s revealing.

Given you properly recycle and reuse akadama (about 60-75% in my many trials) it becomes even very inexpensive. (Kanuma recycles too, but I need more data… seems like about the same.) As does lava and pumice which recycle at about 95%.

That’s the bigger picture on these media

Cheers
DSD sends

Nice summary DSD. I’d add one thing to your point. In bonsai culture, especially for more refined trees, there are times when you need to withhold fertilization. Examples - right after you decandle black pine you remove fertilizer from the tree and reintroduce it later in the growing season. This is to keep the summer needles small and the growth compact. On refined deciduous trees, one withholds fertilizer during the spring push adding it only after the leaves have hardened. There are other examples also.

If you are using a high CEC soil, nutrients will be retained long after fertilizers are removed, undermining your attempts to control nutrient availability. So it’s important to use a low, not a high, CEC medium in bonsai - especially if your trees are in refinement. In development it’s different- you just want to feed and leaf/needle size is not so important. But on refined trees, the practice is to be in control of when nutrients are available to the plant. This much easier when you are using a low CEC medium.

(PS - I also recycle my old bonsai soil).

S

 

[Deep Sea Diver]

Thanks for that addition

These are very important points for folks to help comprehend the evolution of bonsai practices over time on a particular bonsai.

Best
DSD sends

 

[circledisk]

Hmm, 100% pumice with no organic? I would add at least 15% (more likely 20% to 25%) pine bark or sphagnum moss. What are the benefits of 100% pumice or any other 100% inorganic substrate?

sorry to revive this old thread...but when you say 20%, do you mean by weight or by volume relative to the amount of pumice?

 

[Deep Sea Diver]

Bonsai mixes are quoted by volume.

For example 1:1:1 APL = 33% Akadama : 33% Pumice : 33% Lava. A general conifer mix

or say for a newer mix for azaleas

85:10:5 KPBC = 80% Kanuma : 10% Pumice : 5% Biochar

Hope this helps

Cheers
DSD sends

 

[circledisk]

Thanks. I've always done and interpreted as by weight relative to largest ingredient.

 

[circledisk]

IMHO Kiwi sphagnum has been shown to superior than most others for use in our orchids and azaleas then most others, yet I’m sure there are other recipes that would do fine. In fact my wife is experimenting with adding ‘plastic peanuts’ to her orchid mixes instead of clay shards.

For some variety of reasons every time I ask a question about things like “Is pumice the best media for bonsai?” I always get the answer, “It depends....”.

John Muth, at the now closed Bonsai NW store, swore pure pumice in an Anderson flat would help just about any pine in trouble put out plentiful roots and new growth in a year, or so.

As someone said earlier Michael Hagedorn, wrote a nice couple really chapters on media, including the benefits of using akadama and other organics in a mix, their impact on ramification and on why the media composition needs to evolve as trees mature it depends”

At the PB museum, where we work with high grade trees, we mostly use either Boon mix (or straight kanuma for azaleas). Yet @Walter Pall related on youtube he wouldn't touch akadama in his garden media, preferring a straight inorganic mix.

I learned a lot from @markyscott in his resources and threads about media followed by a number of discussions and more with added practice. The upshot of all this information seemed to me to be about media “Its gotta flow and drain, It’s gotta hold then give off water and nutrients over time, and it all depends on the particular tree and situation.... and oh yes a beautiful pot with poor drainage can ruin the effect of a good media.“ I’d recommend both the @markscott resource and a good read of his threads if you haven’t.

Along the line I found this data table in a @markyscott thread on CEC, which I will resurrect to add to the information here. After I-read this I realized another reason why charcoal is in Boon’s mix.

cheers

DSD sends
View attachment 346341

I've had a ton of success putting collected trees in a mix of pumice, sphagnum moss, manure compost from home depot, and charcoal (6 : 2 : 2 : 0.5)

The mix I've used is from bonsai4me https://bonsai4me.com/soil-mixes-for-weak-and-newly-collected-trees-and-yamadori-aftercare/

He does live in the UK though, so YMMV depending on your USDA zone and the type of tree etc.