Potting Mix Tests Results Abbreviated

[NBPCA]

Hi Everyone,

Here are the abbreviated results in a PDF. Just click on the file and save to somewhere; then you can view it.

Potting media tests abreviated.pdf

.

Soil Mix Component Test Results. (Components only!)

I thought I would use Akadama and Kanuma as a known reference point to start with. The reason being that Kanuma and Akadama have been tried, tested and used by the Japanese for a long time and so the properties/performance of the component/soil on its own is known for both Akadama and Kanuma. This may not be directly comparable but it is a start. Kanuma is used 100% on its own for Azalaeas and Akadama can be used on its own for a wide range of plants. Akadama can also be used in blends of components to create your own tailored mix.

I am not advocating that Akadama or Kanuma be your bonsai mix or part of your mix! I am just looking at how it performs and then comparing it to other materials that we can also readily source in Australia.

Proprietary Bonsai mixes made by the Bonsai nurseries and Debco, Amgrow etc are treated as a component or stand alone mix as well. I cannot say exactly what is in each blend and to a certain extent it is irrelevant as I am looking at its performance; not what it is made up of.

How I did it.

Firstly with Akadama and Kanuma, and some other products, you buy them in bags of a certain size. Names of sizes can be confusing so I have designated a particle size that is being used. I sieved out all dust that is .6mm in size and disposed of it. I then graded the rest into size ranges to find out what percentage has been wasted as dust and then what size particles are left.

Particle size and shape are important to its performance; weight not so important except to lighten mix.

I have sieves that give me + .6mm to -2mm, 2mm to -4mm, 4mm to -7mm and over 7mm(Approximate)

The test results below firstly show the performance of the component with all its sizes in the ratios found and put into the pot in layers in 5”/125mm pots. Coarsest part of the component on bottom, then middling coarse then smallest on top. With some components like the propagation sand/ 3mm brown pebble they are just used straight out of the bag.

I also tested each individual particle size’s performance as well, but there is too much info at this point. I can discuss the individual components and individual component’s particle sizes as we go on. It is important! Particle size is everything! (Well almost)

Each of the components behave differently in interesting ways and it is hard to describe. Some are very easy to dry; some are hard to dry; some behave very differently in small and large size particles; some not so much; some hardly at all.


Labels.

Medium/Component. Name of the component I am testing
KG Dry. How much a pot full of the dry component weighed. We then put in water to lip of pot to soak
KG Drained. After 10 minutes of soaking we then let drain for 10 mins then weighed.
Water Gain KG. Weight of water gained/held/absorbed after draining for 10 mins
(NOTE. Some components are very light and increase in weight dramatically when wet but still hold/gain/absorb the same amount as some other components; so we have not expressed water gain as a % of dry weight of the component!)
PH. I used the Manutec test kit, liquid then powder, and these are our results on the day. Please allow for some leeway.
Water Table. Amount of water that freely drained out of the component when it was tipped on its side after 60 mins. Expressed as grams although we could do % of KG
AFPT. Air Filled Porosity Test. Component was placed into an open top container (1 ltr) immersed into water; wet then water allowed to drain, captured and weighed. If 300 mls of water were captured it is expressed as 30% AFP

Results....


Well, what do we make of it all?

Firstly, Kanuma. A mix for Azaleas. I have always had a brown thumb when it came to Azalea but we now have a Satsuki azalea growing in 100% Kanuma at the collection and it is happy as Larry. I will probably grow all my Azalea at home and in the Collection in Kanuma from now on.

The difference in performance from my tests show that Kanuma and Akadama have same PH; same water table and similar Air Filled Porosity (at least on day one). Kanuma is lighter and absorbs/holds more water however.

Going by PH I definitely would not try Mt Sylvia Diatomite, Spongalite or Attapulgite on their own as a replacement for Kanuma. Maidenwell Diatomite is right PH but has lower water table, higher air filled porosity and higher water gain/ absorbing quality(which surprised me!) Worth trying? Yes in my opinion.

Perlite? Don’t know! But probably not practical.

Akadama. A general mix or component?

Moderate weight, moderate water gain/holding, slightly acid PH, low water table and moderately high Air filled porosity.

The folks in WA are using it in various ways and it seems to perform OK over there with extra water holding components added. It will compact over time I presume and lose some air filled porosity. I will be repotting 2 WA trees this year and will let you know how they look in the Akadama after a few years in WA and a few years here growing nicely.

My feeling is that most of the other components could compliment Akadama or replace the Akadama in Australia in most cases. In Japan they have a summer monsoon and the trees drain quick enough not to water log bonsai; they would tilt the tree to aid drainage if necessary. In Australia we can have hot, humid, wet summers; or hot, arid dry, no rain summers; or cool, dryish, dry summers; depending where you live.

Apparently it is no good in countries/ areas that have long, cold, wet winters as the Akadama turns to mush.

Unsurprisingly Crushed brick isn’t way wide of the mark.

Also Chinese Akadama behaves similar to Akadama but without as much water gain. As it is a hard, baked product I am not surprised.

By reputation alone Maidenwell Diatomite may be our equivalent to Akadama. It is light, gains/absorbs water, has a low water table, highish Air filled porosity and same PH or similar, and a nice brown color.

My growing trials will answer some of these questions.

I have more information on the performance of the various particle sizes in each product. Size of particle can slow or increase drainage as needed.

I will post separately and discuss separately,

Grant

[Jow]

Thanks for doing this Grant, you have discovered some interesting results.

I look forward to the next lot of results and your interperation of them.

[Gareth]

Hi Grant,

So what i am gathering from this information, is that what we are generally looking for is a medium that has a good water gain (for stored water for the plant to access but so as to not keep the roots "wet" or "swimming"), a low water table (to prevent root rot so the plants roots are not physically sitting in water and so aeration can take place) the appropriate pH (which if too low we can manipulate up) and a high air filled porosity (for oxygen exchange to the roots), am i on the right track?

Gareth

[Josh7]

Grant, great work mate. The time and effort you have put into this is appreciated by us all (if i can speak for us all).
I am using Maidenwell Diatomite for the first time (in a 50/50 mix with Aussie Native Potting mix - pine bark), and like you, was surprised with how much water it actually does hold (which is great for summer).
Will shortly find out about the aeration by watching my trees and how they respond to it.

Once again, thanks for a great study that has informed everyone who casts an eye over it. I'm sure it will change the way in which a lot of us repot in the future....

[Grant Bowie]

Hi Grant,

So what i am gathering from this information, is that what we are generally looking for is a medium that has a good water gain (for stored water for the plant to access but so as to not keep the roots "wet" or "swimming"), a low water table (to prevent root rot so the plants roots are not physically sitting in water and so aeration can take place) the appropriate pH (which if too low we can manipulate up) and a high air filled porosity (for oxygen exchange to the roots), am i on the right track?

Gareth

I think so. I am testing some blends of the components to see how they work together, and also on their own, with some Ash seedlings in them.

If you need a dryer mix you can use other components or larger particles.

If you need a wetter mix you can use other components or smaller particles.

Some components will dry out qicker or slower and act differently when in combination so it is an art to blend a mix for yourself.

Grant

[Grant Bowie]

Grant, great work mate. The time and effort you have put into this is appreciated by us all (if i can speak for us all).
I am using Maidenwell Diatomite for the first time (in a 50/50 mix with Aussie Native Potting mix - pine bark), and like you, was surprised with how much water it actually does hold (which is great for summer).
Will shortly find out about the aeration by watching my trees and how they respond to it.

Once again, thanks for a great study that has informed everyone who casts an eye over it. I'm sure it will change the way in which a lot of us repot in the future....

Today I put a moisture probe into a recently wetted pot of kanuma and a pot of Attapulgite.

The air filled porosity for the two is the same but the Attapulgite was off the scale (wet) and the kanuma was registering on the dry side.

There are still more tests I need to do!

Grant

[Jan]

Very interesting; thanks for undertaking such extensive testing.

As you are in a similar climate to my own, I will certainly be “watching this space” with interest in future,

Jan

[Delilah]

Hi, sorry, new here...

- What does the "Water Table" measure tell us?

- What does "AFPT" mean?

Thanks

[NBPCA]

Hi, sorry, new here...

- What does the "Water Table" measure tell us?

- What does "AFPT" mean?

Thanks

Water table was the amount of water that remained in the mix/component, after one hour, that emptied out when tipped on an angle. This water is probably held near the bottom of the pot and in prolonged wet conditions could be a problem with waterlogging and root rot for instance.

AFPT is Air Filled Porosity Test. We fill a container with potting mix/component (say 1 litre) and then submerge in water but not loosing or disturbing the mix. We then remove the container from the water and measure the amount of water that immediately drains out till it stops dripping. This tells us now how much air is in the mix. Too high a percentage of air in the mix could indicate it would be hard to keep it watered whereas too low a percentage of air in the mix could indicate the mix will stay too wet and not drain well.

I can't yet say what I consider a good percentage yet for Canberra where I reside, and it will of course be different for various locations and climates.

I am doing some growing tests at the moment and, so far, most if not all of the Ash seelings after being dug up, root trimmed and placed into various mixes and single components of mixes, are budding nicely. The summer will tell how they do in pure blue metal, Zeolite, Diatomite, Attapulgite and blended mixes.

Grant

[NBPCA]

Hi all (especially Pup),

We repotted the large Melaleuca rhaphiophylla today and it had been in a mix of 50% Akadama and 50% Carnarvon River Gravel for 3 years.

It had become very slow for the water to penetrate so we waited for signs of growth and then repotted.

In the mix we removed there was absolutely no trace of the Akadama! It had completely disappeared and there was just gravel and lots of healthy roots! Certainly no Akadama recogniseable or reuseable.

Interesting! We put it back into a mix of 50% Akadama and 50% of a mix of various gravels.

We shall see how it performs over the next 2 years. I will repot it in two year intervals from now on. If I keep this job for the next 50 years that should be 25 repots and a fair indication of how Akadama goes in Canberra.

Tongue firmly in cheek,

Grant

[Graeme]

If I keep this job for the next 50 years .

Tongue firmly in cheek,
Grant

And an opotomistic heart mate, the shame being we are not as young as we would like to be, or think we are.

I would also like to echo all the others who have offered up their thanks for the work you are putting in Grant. I did a lot of similar research into potting mediums, following some "spirited" discussions with "those" two lladies from Adelaide, while I was up in Darwin. Trouble was, unlike you, I was slack and did not record any findings and only used them for my own growing purposes (plus fellow Club members of course). Now, having been away from the active study phase for a while I have lost all that information, as you do.Once again, thank you for not only your efforts, but for recording those efforts.

[NBPCA]

Hi all,

As promised I will have some preliminary/ongoing results from the trial growing of Desert Ash (Fraxinus angustifolia) in various components and blends.

Had some hits and some misses. Details to come.

Grant

Potting mix trials 2010 004 - Copy.JPG

[NBPCA]

OK, Here is a PDF with some test results

Potting mix component growing trials results.pdf

Please don't read too much into the minutiae of the results. Just because a component performs badly on its own is not surprising.

I will post some photos comparing various results. Also some other trees may do better in gravels for instance than Ash; say pines or junipers

Also still to come are the requested blends results so far.

I am considering fertilising the Liqud only group with triple dose Liquid. What do you think?

Grant

[Pup]

G,day Grant that is interesting, as I have also noted that the Akadama seems to disappear, as does the coco peat leaving just the Carnarvon river gravel. Some of the original soil on trees that have not had as many re pots still persists.

Like Graeme, says thank you for your efforts, they are much appreciated. Now how is it recovering?, putting out new growth. I have had quite a few flowers this year.

Cheers Pup

[NBPCA]

G,day Grant that is interesting, as I have also noted that the Akadama seems to disappear, as does the coco peat leaving just the Carnarvon river gravel. Some of the original soil on trees that have not had as many re pots still persists.

Like Graeme, says thank you for your efforts, they are much appreciated. Now how is it recovering?, putting out new growth. I have had quite a few flowers this year.

Cheers Pup

Hi Pup,

The Melaleuca is doing fine after its repot. It shed a few internal leaves but is powering away now that the warmer weather has arrived finally.

No flowers.

Grant