Question for boons mix users

[Biofusion]

Hi guys,

Has anyone here seen the boons mix ingredients up close as used by boon (or might I say, any that have been to Japan and seen it used as it was used way before boon started to advocate its use, he just made it popular)

I'm wondering the scoria used in the pumice, scoria, akadama mix was hard scoria or soft scoria, and what colour it was?

[cre8ivbonsai]

Hi Biofusion, ahh the good old soil mix discussion (I have not seen Boon's mix in person.)

When I first heard of Boon's mix, I searched for those exact ingredients, and in my first attempt used hard scoria (the regular stuff from the hardware store) the smallest I could find was about 10mm - I did find that it was too hard, large and too free draining for most species (my PJF did well though). The next year I found a garden centre that supplies soft red scoria (I think they use it for tennis courts?) although it was half fines, it was still quite cheap, and I think a better component to my general bonsai mix. I still use hard scoria as a drainage layer in the bottom of poly grow boxes.

The one ingredient I was recommended to add by all experienced growers I talked to and showed was small aged pine bark chips (commonly used for orchids). Most declared they simply use diatomite and aged pine bark chips 50/50.

Since then I resolved to finding the ingredients I could obtain locally and easily (a bit like cooking really): aged pine bark chips, diatomite, crushed granite, soft scoria, akadama (if I can get it), and a pinch of charcoal. All sieved to exclude the fines, and graded. Quite the cocktail I know, but I've really just read through other people's choices and combined them into my own mix. I'm not a soil scientist so I've sort of taken the scattergun approach.

I'm going to try adding some zeolite this time round after reading about it's beneficial properties, and maybe pumice in the future.


This is my and experience so far, and is under constant refinement depending on: ingredients available, species, and watering habits.

Ryan

[Biofusion]

Yeah, I hear what your saying mate.

I'm just trying to figure out if this mix Indeed uses hard or soft scoria (lava)

I mean to say boon uses it, as did his master, and Ryan Neil uses it, and I think you could safely assume limits uses it too.

Word out there is that it is a very common mix in Japan, and has been used even before boon started advocating it.

So I'm wondering if it matter if the scoria is hard or soft for boons mix, obviously soft I think is better, but if the Japanese are using hard scoria in this mix, and you. Can find it at the right size, well, it would do the trick.

[cre8ivbonsai]

Yep, understand. Just from feel the soft scoria has a similar density to akadama (different composition I know), but I started using it a bit of a substitute due to the scarcity of akadama.

In the 'Boon's' mix the hard scoria might be used to facilitate drainage

I've also wondered "Lava Rock" (as the Americans put it) the same as our "Scoria"

[Scott Roxburgh]

I have seen Boon mix up close, and it is hard Akadama, clean Pumice, and hard lava/hard scoria (just like the 10mm in landscape stores but a finer grade). In the states they have a red and a black separate, I've only ever been able to get hold of a mix of the two together and my sieve wont sieve out the black

I'd like to mention that it was termed 'Boon mix' by his students not by Boon.

I advocate its use as the results Boon gets in a climate very similar to mine/Sydney is good enough for me. I have been using it for a few years now and the results have been pleasing with the care that I give my trees.

I'll get some pics of the individual components and the blend that I use at home.

Leong at Bonsai South has the fine scoria that I use, but I you can just use an extra part pumice, it does roughly the same job.

[Biofusion]

Interesting, I think that what I'm seeing here is that the scoria acts to open up the mix. It could be said that diatomite would do the same job, but diatomite is usually flatter, and packs more, or at least it seems as though it would.

So as you say, pumice and scoria would seve to do the same thing in "opening up" the mix to allow more air to get in.

The question is though, why in boons mix do they use both pumice and scoria?

I would like to know the reason behind it and what each individual component offers.

And before someone says it, this is a my mix is better than your mix thread lol.

Just trying to find a reason to why it's used, or in this case why both components are used

[bodhidharma]

Just trying to find a reason to why it's used, or in this case why both components are used

Probably because that is the way he has always done it . I have used scoria in my mix for years but it is now difficult to get it small enough (5mm). It would certainly give great drainage with water retentive qualities using both.

[Biofusion]

Yes but there has to be a reason why they use both scoria AND pumice.

The Japanese wouldn't use them both together "just cause".

Maybe an email to boon might yield some enlightenment on the matter.

[shibui]

The hard particles in a mix are not only about 'opening' the mix and providing drainage. Diatomite and Zeolite have microscopic lattice structure so they have a very high CEC (cation exchange capacity) and act like a sponge to hold water and nutrients in the mix for your plants (while still leaving plenty of air spaces between particles. Other hard particles (granite, etc) have lower CEC so nutrients leach out quicker. Pumice has lots of air bubbles so it may also have the ability to store water and nutrients. Scoria will probably have a CEC somewhere between gravel and the others. Maybe someone can search and find some CEC and water holding figures on a few of these components.

Another factor is density. Larger pots can be pretty heavy so lighter (less dense) components in the mix can take a load off your back. Pumice has very low density (floats on water) so using it will give a lighter weight mix.

[Biofusion]

Well here it is, I got a response already,

- the root growth is different between the two. Pumice stays dryer and promotes more root growth (I think due to air porosity in the mix is what he means here). Lava (scoria) will cause the roots to split and create more fine feeder roots.

He goes on to say that The scoria holds more water, which is why I think, that it causes more fine feeder roots, as I have seen with zeolite and diatomite.

He also goes on to say that if you can't get one or the other, that you can leave it out and substitute that part with the material you do have.

So I'm thinking, that zeolite especially, but probably diatomite as well, might very well be an easily available alternative to scoria, since, by the sound of it, it does the same job in promoting root growth.

"Opening up" the mix, could then be achieved with pumice.
Akadama is in there for water holding capacity as well as CEC.

So with CEC covered with the zeolite, and water holding capacity covered with the zeolite (which stays pretty moist) and the diatomite, I'm thinking that a mix of

-diatomite
-pumice
-zeolite

Might very well do the trick. Anyone tried this combo?

[Damian Bee]

As far as opening a mix up goes, large particles are the go. If you are thinking any old inorganic will open a mix up, fine particles like scoria sand or dust will soon have you running for the nose pegs

Most scoria (in Victoria) is only good for significant moisture retention when using the fines. The moisture held by the larger particles is minimal in comparison to pumice or diatomite.
Scoria was once used as a major part of potting mixes before composted pine was widely available. Due to its weight it was eventually ditched for lighter materials. I use it sometimes as a cheap bulking agent but for all of the cleaning and screening I don't bother much anymore as the time cost is too great.
Scoria is rough so it can help to split roots but so too is pumice also has a rough surface and depending on how much fines are in your mix will help to create more fine roots with the exception of plant species which already have fine roots like Rhododendron etc.
The danger with scoria can be that water sits in the bubbles on its surface causing the mixture to hold too much water as I found with some mixes and you need to be sure of the product you are using as the PH can be a problem.
Blue metal, (crushed and screened basalt) can be good, it's very heavy (density of 2.8-3.1 ton per m3) but it is rough and has a neutral PH. It's problem being that like scoria it holds very little moisture.

Zeolites best purpose is to absorb excess nutrients and release them as required and to increase cation exchange, it has some of the highest known levels for products used in potting mixes and agricultural applications. As far as moisture retention goes, it is not that great unless you are using the fine stuff. It has a PH of somewhere around 6 depending on the source and is most effectively used at a rate of no more than 20%.

Diatomite is great stuff being lightweight and relatively cheap, its only problem (if you are using Kleensorb) is its PH which can be as high as 8.6 and therefore needs buffering with an acid component such as peat or pine nuggets but in the inorganic mix you might use something like zeolite and perlite. Pumice is ok but generally has an almost neutral PH.

One component that I have not seen discussed here is crushed granite. I recall getting lost with Boon at Hanging Rock and discussing various components, one of which was crushed granite. Again, depending on its source, it can be a great part of a mix, some granites are high in compounds like potassium. It doesn't hold much water if it is hard but if semi decomposed it is a little clayey and certainly rough in texture. As far as PH goes the last batch I had was around 6.5 which was great for most trees. Those that had it in the mix were very healthy.

Quartz sand is only good as a small part if any as it holds water only on its surface and has little to offer in the way of CEC. If you are already using inorganics then it is not really necessary considering that you want the absolute most for your tree out of the limited space you have in the pot which I think is the most important thing to remember for your mixes.

[Biofusion]

Some interesting points you raise.

Boon said that scoria holds more water than pumice, and that pumice stays drier, I would think this statement means it increases the aeration of the mix more so than the scoria?

In my experience scoria stays bloody wet, almost soggy.

In my experience zeolite also stays very very wet, drains well, but hold a lot of
Moisture, your right that it also holds a lot of fert and nutrient, and is exactly why it is used as the primary nutrient storage and transport in most mediums. I have used this at up to 40% with no problems, but I suppose you would have to fertilise more at the start. To avoid the tree from become deprived of nutrient.

I agree on the pH issue, in that depending on the medium it may need correcting. Especially when we are dealing with volcanic aggregates mostly.

Who else has had the experience with zeolite staying wetter than most mediums. I know ken uses a lot of zeolite, KC, care to weigh in?

[Damian Bee]

What size zeolite are you using bio?
I find that the 0.5-2mm stays very wet due mostly to particle size.

[Biofusion]

Around 2-4mm.

I have just been reading grants soil results.

Although zeolite doesn't in itself absorb a lot of water, the water table it has was one of the highest, indicating that the "wetness" is in fact to due to it absorbing water into itself, but trapping water between its particles, or so it would seem,

It still has a decent AFP, but it traps a lot of moisture.

[Grant Bowie]

lots of different mixes work well and it does depend on where you live as to what will be best for you.(hot, cold, dry, humid, wet, arid etc)

size of particles are also important.

Good luck with your quest.

Grant