Potting Mix Tests Results Abbreviated

[NBPCA]

So far from my tests I believe that Akadama and Kanuma used on their own are OK but not the be all and end all; but Diatomite is best blended with something else.

Grant

[63pmp]

HI Grant,

Some musings I have had regarding your research.

My back of a envelope calculation for nitrosol (website says 12.2% N) gives 540 ppm N at 40 mL of nitrosol in 9L of water. While this is high for a nutrient solution, it is only being applied once a fortnight. Most of the N supplied by the nitrosol would have leached from the potting media after only a few days. It is no wonder the osmocote performed better as it constantly releases N, while nitrosol was only at an appropriate strength for a couple of days, (maybe only one day!!) This is because the concentration of N in the potting mix has to be high enough for it to enter the roots by osmosis. Too dilute and the N will not enter the root. Watering the plant could easily over dilute the N in the mix.

Tripling the concentration would give you a very strong solution, approximately 1500 ppm N. But faced with the same problem of 2weeks between feeds, again, most of the N would leach out before plant uptake.

Another factor is knowing what form the N takes in the nitrosol. If it is mostly organic, it would take several days for bacteria to convert to an inorganic form which could be utilized by the plants. Since many of the mixes have little or no organics in them, it would take many weeks for bacteria to develop enough to take up much of the nitrosol, so most of the nitrosol would probably have been lost by leaching. (This would produce a delay in the Nitrosol plants development and so the plants would be smaller than the osmocote plants) Osmocote on the other hand is predominantly urea based N, which it is releasing continuously, it too requires bacteria to convert it to Nitrate, but plants can take up urea and convert it themselves. I wonder how much of the N from the osmocote was taken up by the plants in comparison to N from nitrosol.

I would recommend feeding the plants with 20 ml Nitrosol/9l water every 3-4 days. This would provide a more steady supply of N. I think it is better to feed a little often, (much like osmocote does) than to give a whole lot infrequently.

How much Osmocote do you add to the mixes? It is very difficult to judge how much N is released from the prills, of course, but a comparison of the total amount of N supplied by the two different fertilizers might be interesting.

Did you also fertilize the osmocote mixes with the nitrosol liquid feed? I'm not clear on this.

It would also be interesting to see how much the pH has changed in the different mixes over the course of the trial using these two fertilizers.

Regards

Paul

[Bretts]

Walter suggests different and he shows us his results are excellent

[Grant Bowie]

hi Brett,

yes that is why I am trialling things; rather than only going on say so from no matter who.

Grant

[Grant Bowie]

HI Grant,

Some musings I have had regarding your research.

My back of a envelope calculation for nitrosol (website says 12.2% N) gives 540 ppm N at 40 mL of nitrosol in 9L of water. While this is high for a nutrient solution, it is only being applied once a fortnight. Most of the N supplied by the nitrosol would have leached from the potting media after only a few days. It is no wonder the osmocote performed better as it constantly releases N, while nitrosol was only at an appropriate strength for a couple of days, (maybe only one day!!) This is because the concentration of N in the potting mix has to be high enough for it to enter the roots by osmosis. Too dilute and the N will not enter the root. Watering the plant could easily over dilute the N in the mix.

Tripling the concentration would give you a very strong solution, approximately 1500 ppm N. But faced with the same problem of 2weeks between feeds, again, most of the N would leach out before plant uptake.

Another factor is knowing what form the N takes in the nitrosol. If it is mostly organic, it would take several days for bacteria to convert to an inorganic form which could be utilized by the plants. Since many of the mixes have little or no organics in them, it would take many weeks for bacteria to develop enough to take up much of the nitrosol, so most of the nitrosol would probably have been lost by leaching. (This would produce a delay in the Nitrosol plants development and so the plants would be smaller than the osmocote plants) Osmocote on the other hand is predominantly urea based N, which it is releasing continuously, it too requires bacteria to convert it to Nitrate, but plants can take up urea and convert it themselves. I wonder how much of the N from the osmocote was taken up by the plants in comparison to N from nitrosol.

I would recommend feeding the plants with 20 ml Nitrosol/9l water every 3-4 days. This would provide a more steady supply of N. I think it is better to feed a little often, (much like osmocote does) than to give a whole lot infrequently.

How much Osmocote do you add to the mixes? It is very difficult to judge how much N is released from the prills, of course, but a comparison of the total amount of N supplied by the two different fertilizers might be interesting.

Did you also fertilize the osmocote mixes with the nitrosol liquid feed? I'm not clear on this.

It would also be interesting to see how much the pH has changed in the different mixes over the course of the trial using these two fertilizers.

Regards

Paul

To start with all the trials are using manufacturers recommended dose and frequency. You have to start somewhere.

I have always made it clear that those with Osmocote are also being fed with nitrosol or equvalent as well.

NPK of each product has also been listed.

grant

[Scott Roxburgh]

Walter suggests different and he shows us his results are excellent

Sorry Brett different to what statement?

[63pmp]

As I said, they are only musings.

Several people were commenting on how good osmocote treated mix is. I'm not sure this trial shows this, with this trial one would expect the osmocote treated pots to put on more growth as they are fed more than the nitrosol alone mixes. That is what I was trying to understand and mused upon. Once potting ingredients are mixed together it is important how treatments (fertilizer) are applied and assessed. Within treatment (nitrosol fertilized mixes only (or osmocote+nitrosol only)) comparisons of plant growth relate to the mixes properties; between treatments (nitrosol v osmocote) we are comparing fertilizers, not mixes.

I understand Walter feeds every now and then, and with high concentrations at a time. Which is OK. Other people feed often with less, and they get excellent results as well. I think its valuable to at least to try and understand what they doing, rather then just taking their opinion at face value. (I can see several ways in which Walter's method could lead to trouble, though this isn't the place to discuss this).

Thanks for your reply Grant, I appreciate the effort you have made with these trials.

Paul

[Bretts]

Walter suggests different and he shows us his results are excellent

Sorry Brett different to what statement?

Tripling the concentration would give you a very strong solution, approximately 1500 ppm N. But faced with the same problem of 2weeks between feeds, again, most of the N would leach out before plant uptake.
.....................................................
I would recommend feeding the plants with 20 ml Nitrosol/9l water every 3-4 days. This would provide a more steady supply of N. I think it is better to feed a little often, (much like osmocote does) than to give a whole lot infrequently.

[NBPCA]

Hi all,

After almost 6 months here are some results and observations on the potting components and some blends growing tests.

NOTE!!! This is a test of the components on their own first and then some blends. It is not a test of fertilizers; however I grew them in 2 batches to use different fertilizing regimes.

One is with Osmocote in the mix and also fed with liquid at the manufacturers dose rate and frequency. This is how I grow my bonsai and nursery stock.

The other is just liquid feed at the manufactureres dose rate and frequency. After about 4 months it was so obvious that the plants with Osmocote and Liquid were doing so much better than those only on liquid that I tripled the rate(as recommended by Walter Pall)

This is the ground line for the tests so far,

Grant

[NBPCA]

First the components only.

I would say that in all cases the components on their own performed poorly compared to a well thought out blend of the components/media. This is contrary to what we are being told by some quarters but that is my observation and opinion after these tests. However these tests are with just one type of tree (Ash) and they are seedling and not fully established bonsai. For instance Pines may grow well in Decomposed granite but not the Ash etc.

The observations below are from both sets of fertilizing regimes but I would not at the moment recommend Liquid only fertilising as the difference was quite stark.

Components that on their own did very poorly or trees did not survive;[
]Carnarvon River Gravel
Blue Metal
Scoria
Decomposed Granite
Crushed Brick
Perlite
Zeolite
3mm Brown Pebble

Components that on their own did only marginally better or fair;
Akadama
Spongelite
Propigation sand
Chinese Akadama
Diatomite Maidenwell

Components that on their own grew well/OK or good
Attapulgite
Sashi Eda
Amgrow
Diatomite Mount Sylvia

Component that on its own grew the best was;
Kanuma

[NBPCA]

Some observations;

Maidenwell Diatomite on its own was nowhere near as good as I thought it might be; at least in this case of seedlings only.

Mt Sylvia Diatomite and Attapulgite on their own were OK but I found the trees were a bit wobbly.

Kanuma on its own performed well as expected; but I did not expect it to be the best in this test.

Akadama grew the plants OK but a bit stunted compared to some others. This was a surprise to me.

The Chinese Akadama grew lots of fine roots but it appears to be breaking down and staying wet.

The bagged mix from Sashi Eda and Amgrow grew the seedlings well in both cases. I thought the Amgrow mix might have misbehaved as it did compact a lot early on and may still break down in time.

Grant

[NBPCA]

OK; now for the results from the blends of the components.

Here I grew advanced seedlings in a 6" 150mm pot.

As before they were grown in two batches and once again the those grown with Osmocote in the mix and fed with liquid did dramatically better than just the liquid feriliser as well.

First the worst perfomers by far were;
50% Diatomite and 50% Spongelite
50% Crushed Brick and 50% Perlite

Next are those I would rate as having grown well;
75% Chinese Akadama and 25% Coco Peat
50% Crushed Brick and 50% Richgro
66%Diatomite and 33% Zeolite
75% Carnarvon River Gravel and 25% Coco Peat
50% Diatomite and 50% Richgro
50% Akadama and 50% Carnarvon River Gravel
33% Akadama and 33% Diatomite and 33% Zeolite

Two mixes stood out above all the rest and they were;
50% Diatomite and 10% Zeolite and 20% Carnarvon River Gravel and 20% Coco Peat
25% Large Carnarvon River Gravel and 25% Small Carnarvon River Gravel and 25% Richgro and 25% Coco Peat.

So it shows that trees/ bonsai can grow in just about anything but some mixes or components will perform better than others; and that certain trees will probably have different preferences as well. For instance I am growing a figg in the worst performing mix of Crushed Brick and Perlite and it is doing very well.

As to growing in 100% Diatomite or Akadama or any other component on its own; I would not recomend it but that is not to say it wont work.

Grant

[NBPCA]

What is the next step in this series of tests?

I will probably grow on a number of the trees over the next few years and inspect the root systems(Bare Root them) in various mixes and see how they go.

I could see how they perform in say 100% Diatomite/Akadama/Kanuma etc once they are more established and see if that makes a difference.

Other suggestions welcome.

Grant

[Bretts]

That's interesting Grant.
My hunch with 100 percent mixes in general is that you can run into pH issues. The mixes in general act as a buffer to any pH issues. Akadama is one that seemed to be an exception to this rule with me and I thought Diatomite Maidenwell was much the same.

I was suprised to see Attapulgite (Chandlers kitty litter) in the "Components that on their own grew well/OK or good" list. I had always used it only in a mix and when I experimented with it at 100% with a JBP seedling I had pH issues. the seedling was yellow. Did not think it would make the Winter but it did and recovered in an akadama mix this year I am still mucking around with Attapulgite 100% though.

The 50% Diatomite and 50% Spongelite mix was that with the high pH diatomite.

I have a bunch of tridents growing in 100% Spongelite. More from necessity/laziness than anything and apart from being a little light in colour which is probably lack of nutrients they are going quite strong.
I also have a hornbeam seedling in 100% diatomite mid pH and it is going at least as strong as any of the others.

It just gets more confusing

Oh did you notice any improvement when you stepped up the fertilising?

[kcpoole]

nice work
Brett, the high PH Diatomite is Mt Sylvia, so yea it was

This sort of backs up my own tests on larger trees that Akadama on its own is not real great but Kanuma is.

Also does not surprise me that Diatomite Zeolite works well ( all I use now), and that if you were to add peat to it might do even better if you need to make it more water retentive. ( i do not as Mine stay well hydrated all day anyway


Ken