Bonsai soil questions/alternatives?

Marty, that data should be quite useful, and may even save me some money! There is an O’Reilly’s in town, and if more of it’s particles of more appropriate size than the 8822 from NAPA, then I will end up screening out less and more of my money will be going to usable substrate. I will look for down to earth. I’m not too too far from Columbus, and I head up that way occasionally to see my family anyway.
BTW, I was under the impression that lava rock and pumice were synonymous? Is that incorrect?
I found out the other day that our local brick manufacturer will sell me half a ton of crushed brick for $26.

Afellure wrote:Bougies, thank you for all that information. I’m gonna research how to properly measure WHC and CEC today. I’m curious to compare the mix I made with other things. How does one determine ideal quantifications of those qualities? From a cursory search, there isn’t much solid data on that but some stronger general consensuses. If it’s mostly trial and error (as there are many variables and I have learned they there is rarely only one “good” answer) then it seems like it might be a good idea to pot up two or three of the same type/age/size of trees in each of the substrates with different WHC/CEC values within the reasonable range of those values that seem to be more popular. Grow them in that for a year or two trying to keep all other variables the same, then see which trees are “happiest”. May need to repeat this for other species with different growth patterns/etc.

I don't know that you'd get the data you need that way, I fear that between the small sample size and the high variability of so many other elements (trees' genetics, placement relative to each other, etc etc), that you could get a 'false positive' and think you found the best mix when in fact it wasn't.... WHC and CEC are things I've been collecting data on because there's different #'s everywhere, a good starting-point is post#2 in this thread:
https://www.bonsainut.com/threads/cation-exchange-capacity-and-water-retention-rates-list.13754/
but you'll find varying #'s and that's due to both problems with accuracy *as well as* the fact that there is simply no fixed # for some of these, for instance if we're considering scoria/lava, the WHC for some particles is clearly different than other particles, if you open a bag you'll find pieces that are half-holes and so soft you can crumble with your fingers, while finding other pieces that feel like real rocks- the WHC of those is drastically different, so averages are all you can work for. *But*, that's really all you need, so long as you're able to be sure your mix has the attributes you need*, you'll literally be able to tweak things based on what your optimal watering regimen is (ie, lighter mixes if you work from home and can water as often-as-needed, and heavier mixes if not), there's nothing inherently special about any 1 particular aggregate so you can use an almost infinite amount of combinations to achieve what you need*

(*"Need", I'm using that to mean a mix that:
- has maximal or near-maximal porosity for air to get in & around the aggregate & roots,
- has the water-retention level *you* want (in context of only pebbles & peat, the peat% would be a direct correlate of how often you wanted to water; if you wanted 'ideal', you'd use *only* pebbles and you'd setup an automated, top-drip hydro system, there'd be maximal air and constant, homogeneous nutrient availability (modern bonsai-growing has a lot in-common w/ top-fed hydro setups, we just don't collect/re-use our run-off!)
- drains freely (this is of a part with my first requirement but isn't inherent to it, you can have a mix with mostly-aerated substrate *as well as* a layer along the bottom of collected-fines, this would reduce your ability to count on your fertigation basically just 'passing through'!)
)

If you think about it, it's really just figuring-out the WHC capacity you need, past that there's fertilization BUT, let's say you still have very low overalll-CEC, you can compensate for that by simply using timed-release/granular ferts (especially useful when mixed-into the soil instead of only top-dressed), and the only other thing is managing those 2 factors *in the context of* having as much porosity throughout the medium as possible (this is why an aggregate's particle-shape is better/worse than others, because the closer a particle is to spherical, the more you're going to max air-in-container with all other things being equal, and the closer it is to flakes the more it'll "tetris" itself into solid areas after repeated waterings & general settling of the substrate, in fact that settling is why I use like 5-10gal of water to 'water-in' substrate when most just use chopsticks, I just want to be sure all the settling is done off-the-bat)

Pumice and lava are both volcanic, but rather different density and hardness. Pumice is low bulk density (I measured 0.3 - 0.50 g/cm^3) and fairly fragile while lava is harder and higher density (0.55 - 0.90 g/cm^3). Lava is generally used to maintain soil structure while the pumice is used to help hold water. The density of the component will depend somewhat upon the particle size and the particle size distribution (small particles fill the gaps between the large particles and increase the bulk density).

One way to evaluate the ability of a soil component to hold water is to:
1) Dry it well (I like to use and oven at 250 deg F) and weigh it,
2) Soak it in water for several hours,
3) Dump it on a screen that holds all of the particles to drain,
4) Weigh the damp soil (weighing it on the screen works well if you know the screen weight)
5) Divide the wet weight by the dry weight, subtract 1, and convert to percent
I have also done steps 2-4 in a Styrofoam cup by cutting several slits in the bottom of the cup to simulate a pot. Quick summary of results are:
Wet H2O%
Lava 26%
Pumice 62%
Akadama 45%
Diatomic Rock 98%
O'Reilly's Floor Dry 116%
NAPA Oil Dry 163%
I believe that the behavior of the last 3 components demonstrates that smaller particles hold more water due to surface tension - i.e. more of the pore space is filled with water clinging to the particles and bridging the gaps between particles.

Finally, the reference to the Down to Earth products I saw was for Pennsylvania. I have no idea what is in Columbus since I moved west in 1987.

Marty - I dont reckon you have done that experiment with expanded shale (aka haydite), Have you ?

Kevin - I have not looked at Haydite. According to one maker - http://www.digeronimoaggregates.com/technical_info/ - it picks up about 10% water by weight in 24 hours, but they do not give any details on the test. the B size is listed as 3/8" x No. 8 which I read as -3/8" and + 1/8" nominal. If you have some Haydite or a ready source (the use pumice or lava out here instead) why don't you do the dry, weigh, wet, drain, and reweigh test. You don't need a really good scale to get decent information (one from Harbor Freight is fine). You could even do it with a balance beam and a pile of items of the same weight (US quarters 0.20 oz or 5.67 g).

Thanks for the reply Marty... I have already been using it as part of my substrate for about 4-5 years, but have never done the test... I may do so.
(I started using it after learning it is a component in Arthur Joura's mix and I wanted to avoid imported components)

I imagine crushed brick to rate close to lava in that % water test.

Dave Leppo wrote:I imagine crushed brick to rate close to lava in that % water test.

I mean...yes? But NO, also! Both brick and scoria/lava have *varying* WHC based on the porosity of what you've actually got, if you take a bag of lava rock mulch you'll be able to find pieces that you can break with your fingers and pieces that are almost as hard as 'regular' rocks, BUT - so far as averages/general-approximations go - I'd imagine you're close, I'd guess crushed brick to hold slightly less but more than, say, crushed ceramics (regular ceramics not the light-fired stuff that's way more absorptive)

I cannot fathom a reason for actually using crushed brick though, except in a case where you've already got it on-site *and* have no other use for it *and* you'd prefer to save the time/$ to simply buy a bag or two of lava-rock-mulch, in either case you're going to have to process (smash, screen/sieve & rinse - though I usually process everything dry, and only rinse when about-to-use), so if you're going to put in 30min smashing/sieving you may as well get what you want, I mean I'm cheap as heck when it comes to this stuff (and I don't drive) and, if I had a pile of bricks to use, I'd *still* go buy a bag of lava rock instead (yup, I bike with them- not fun!) because crushed-brick just sounds like the shape would be...off. Like, you want more spherical shapes when it comes to good-aggregate-shape, I mean if you think about it the flatter the pieces are and/or the more flat-surfaces the pieces have (both of which I expect crushed-brick will be abundant in!), the more they'll end up 'packing together' and forming a tight substrate, if you consider the extreme example it'd be an aggregate that was shaped as thinner rectangles, if you used this you'd find that as they settled-in they would basically become a solid mass, instead of a porous one, basically negating the whole point of switching from potting soil to bonsai-aggregates that allow the AFP (air-filled porosity) of any substrate (aggregate-blend) So I guess that *shattered* brick would be OK as a smaller % of your mix but definitely not a majority, however if you're smashing it and it's old bricks that are more crumbly, and you're getting pieces that are more spherical than flat, go for it! But if you've got lots of thin pieces and/or lots of flat-surfaces on the chunks, I wouldn't use it as substrate (it could still be utilized of course, if you smash them up you could screen the larger ones and save for lining the bottoms of big pots if you do that, and save the smaller ~1-2mm pieces for top-dressings! The only concern I'd have would be pH, I'd definitely look into that as you don't want to find out too-late that bricks are alkaline or something!)

Bougies,

been using crushed red brick for years. The factory, smashes the hollow clay blocks
that are not up to industrial standard.
[Fired earthenware to 1040 deg.C]
The room is about 20 x 20 feet and has a pile over 6 feet high.

Sifters in hand and an hour gives enough 5 mm and 3 mm and brick dust in an
hour to handle a few years of soil mix.

Now that brick is only 1/3 of my soil mix and used for thirsty trees like
Tamarinds or Chlorophora [ Fustic ]
Tests show 100 % can kill trees.

Stuff does not decompose and the shape is roundish, not flat.
Does not compact either.
Closer to the Ball Bearing principle.
Laters.
Khaimraj

* For ficus the mix is 90 %- 5 mm crushed silica based gravel and 10 %
compost , used in a 1" deep pot.

Tamarind, soil uses 1/3 crushed red brick at 5 mm. Over 35 years old
From 3 leafed seedling.
Soil check last year showed only fine feeder roots and no decay of the red brick. About 28 inches tall.

Not to mention that bricks are all made of different stuff depending on where you live...
In the old days, I dont believe anyone was trucking brick making stuff around the country, instead using what was locally available...

For example, here in Milwaukee Wisconsin, we have alot of Cream City Brick made from local clay (which is really high in Lime & Sulpher)

And while the bricks were made of local stuff, the finished bricks themselves were transported around the country (and around the world for Cream City Bricks).

wait... i got lost in all that typing... why is someone using bricks ?
hopefully just to build bonsai benches

ah... cross post with Khai

I do recall that you use crushed brick Khai, as you use really only what is locally available.
I used to use chicken grit, which is just crushed granite, but I no longer do...

as a structural component, i reckon that if the shape is right, it doesnt hurt...
and i applaud you for using what is locally available !!!
(no shipping expensive clay products {coughakadamacough} from around the world)

but i reckon if lava was just as easily available, it would find its way into your mix...

Kevin,

an old IBCER , Carl Rosner used to send me notes on what he was using.
We used to trade info when I called him, but he is out of Bonsai presently.
He used red lava.

By the way my response was more to the actual discussion on the broken brick.
No response to red lava.
Our bricks are exported, done to industrial standards, so no sulphur or unbound lime.
And the crushed shapes are closer to round.

On using other than what I use.
I don't think so, as the gravel, compost and at times, brick grows everything
well, even Celtis.
I also tested a sea built clay, works nicely as well

Also tested 12 mm marbles, 3 mm glass spheres, Leca and hand rolled clay spheres.
The tamarinds didn't like either basalt or granite. Suspect it is alkaline.
Laters
Khaimraj

I use napa 8822 in everything.
I sift it with a rice colander.
I use over 90% of the bag.
I mix it with pumice and lava
It's called Godzilla mix on another forum.
No breakdown like akadama.
No bugs from inorganic whatever.
Miracle grow. No poop for fertilizer.

https://www.youtube.com/watch?v=94UFmzr8RS8

Hope this helps.

M. Frary wrote:I use napa 8822 in everything.
I sift it with a rice colander.
I use over 90% of the bag.
I mix it with pumice and lava
It's called Godzilla mix on another forum.
No breakdown like akadama.
No bugs from inorganic whatever.
Miracle grow. No poop for fertilizer.

ZERO nonsense !!!

Khaimraj Seepersad wrote:Bougies,

been using crushed red brick for years. The factory, smashes the hollow clay blocks
that are not up to industrial standard.
[Fired earthenware to 1040 deg.C]
The room is about 20 x 20 feet and has a pile over 6 feet high.

Sifters in hand and an hour gives enough 5 mm and 3 mm and brick dust in an
hour to handle a few years of soil mix.

Now that brick is only 1/3 of my soil mix and used for thirsty trees like
Tamarinds or Chlorophora [ Fustic ]
Tests show 100 % can kill trees.

Stuff does not decompose and the shape is roundish, not flat.
Does not compact either.
Closer to the Ball Bearing principle.
Laters.
Khaimraj

* For ficus the mix is 90 %- 5 mm crushed silica based gravel and 10 %
compost , used in a 1" deep pot.

Tamarind, soil uses 1/3 crushed red brick at 5 mm. Over 35 years old
From 3 leafed seedling.
Soil check last year showed only fine feeder roots and no decay of the red brick. About 28 inches tall.

That's awesome (both your substrate approach and your Tamarind!!) I had to check to see why you seemed to think I may've disagreed with any of your approach and I want to clarify that what I was saying was contextual, I just meant that if joe schmoe is going to "go the DIY route" for substrate (as I do!), it's a better choice to go buy a couple bags of lava-rock-mulch than a bunch of bricks

IF I were in your situation IE had access to free bricks/sharded-bricks, I'd most-certainly use them!! Can you elaborate on '100% kills'? I'd imagine 100% is just fine....also the way you phrased that makes it sound like you mean you use *more* brick for thirstier plants? I guess I'd have presumed that brick was like scoria/lava, IE there's a varied WHC and CEC but it's basically "all good" so long as you process it right / rinse it / etc, but I would've thought brick would have low WHC(water-hold-capacity) and that a 100% brick substrate would actually require too-frequent waterings! If I were in your position and had that access, my immediate assumption is that it'd replace scoria in almost all instances, and that I'd be adding lots of organics to it for Cypresses but otherwise consider it a good, mostly inert aggregate!

That's cool to hear that they particle-shape isn't prone to being flat, would you say it's more or less 'flat' than typical DE is?

I'm gonna go on a limb and assume your time in this hobby means you've read the following, but for anyone reading this thread I'd strongly suggest reading the following article, it's a beautifully-complete explanation of soil//watering/fertilizing:
http://walter-pall-bonsai.blogspot.com/2010/06/feeding-substrate-and-watering-english.html

I'd heard before about *styrofoam* being used lol, anyways I recently received mail that had styro peanuts and as I went to toss them I thought "nope, let's try it out!" and just the other day I took a root-bound crape myrtle out of its container and slip-potted it into a larger colander where I used 100% styro for the bottom 1/4th of the container, then 50/50 styro // crushed-pine-bark-mulch for most of the rest, then just mulch & rock on the top (forgot styro floated til I was messing with it ), will see how it goes but will hark back to the idea that most-anything can be utilized *so long as* it meets certain criteria (which the linked article goes over), IMO there's never a "best substrate" it's highly variable, even if you discount things like what species it's to be used for, as local-availability should absolutely factor-in (hmmmm, but wait, that can't be right- there must be *some* reason why people spend beaucoup $$ to import akadama and there's no way it's a "japanophile" type thing, it's *gotta* be horticulturally-valuable in a way that can't be achieved w/o akadama.....right? ;P )
[/JK re akadama, to be clear ;D ]