AusBonsai

Bretts wrote:That was what I noticed as exceptional too Grant. I guess if you soak it for some time in a tray of water it will end up with a water table at the bottom. Still have my test pot sitting there I might wack it in a tray and see what happens

I test watered test watered three pots today. All were of sieved and graded material. One was Mt Sylvia diatomie, another pot of crushed brick and another of Chinese Akadama. The Diatomite was almost dryish to the touch but even through within a few hours or so it seemed, whereas the crushed brick was very wet and the Chinese Akadama in between. Not what I was expecting so it will be interesting to compare them all together when I have it all assembled.

Grant

Grant Bowie wrote:

NBPCA wrote:Hi all,

I will eventually be setting up a trial of diatomite and others as growing media and trying various permutations and combinations of them together.

Firstly we will see how much water the various media absorb/or not and then hold onto/or not.

At the collection I have some brand new orchid pots measuring measuring 28cm accross and 11cm deep. The holes are generous and largish so I will use a drainage layer of equal volume of each type of potting media in each pot.

Weigh first, then dunk and let sit in the water for say 10 minutes, then lift and drain and then reweigh each one as it stops draining, and then all at the same time each hour .

(I will donate the various potting materials that I have accumalated as I will use it all up myself eventually.)

Any other suggestions or observations at this time?

Other suggestions are now 1 Air Filled Porosity, 2 PH, 3 drying out times (but you can adjust by particle size)
Grant

A few more tests to add to the list.

Freeze and thaw test, Sit in water test to see if it breaks down, Amount of water needed to saturate and start draining.

Grant

NBPCA wrote:

Bretts wrote:That was what I noticed as exceptional too Grant. I guess if you soak it for some time in a tray of water it will end up with a water table at the bottom. Still have my test pot sitting there I might whack it in a tray and see what happens

I test watered test watered three pots today. All were of sieved and graded material. One was Mt Sylvia diatomie, another pot of crushed brick and another of Chinese Akadama. The Diatomite was almost dryish to the touch but even through within a few hours or so it seemed, whereas the crushed brick was very wet and the Chinese Akadama in between. Not what I was expecting so it will be interesting to compare them all together when I have it all assembled.

Grant

After I did the zeolite diatomite test and found the zeolite looked wetter instantly and for days after that was what I was expecting. The Diatomite water holding capacity seemed to soak up any water table the medium held after draining.
As I figured soaking the diatomite and allowing it to soak up as much water as it could hold would have to result in a water table in that as well. I did another quick test.
I soaked the diatomite for a 1/2 hour or so, took it out and then left the pot to sit for a few hours and as you would expect it had a water table that could be emptied more by tilting the pot.(this was not the case when only heavily watering from above). But without measuring it seemed less than what came out of the zeolite after a few days?
So I was interested what you would find as you where soaking in your test.
I am surprised to find that you also found the lack of a water table in Diatomite even though you dunked the pots. Not sure but I would guess you are dunking the pots but not allowing them to soak.
Might be interesting to do a test of soaking the mediums for say 1/2 hour to make sure they have absorbed as much water as they can. Then at the end of any testing you have been doing(hours or days, whatever has been useful ) You could then measure the volume of water held in the water table after drainage by tilting the pot and measuring the water that came out of each medium/pot. I am predicting they will be very close to each other. With some allowance for different evaporation rates for different mediums (which I guess is minimal) I am sure physics tells us they will have to be the same? But I am curious as it seemed even when I soaked there was a smaller water table in the diatomite!

I let everything soak for around 10 minutes but can do it for longer.

grant

You would think 10mins would be long enough. Can't think of any other reason for the water table to change. Between mediums. I now think Jamie suggested the electrical charge of the mediums would affect the water table. I would have thought that possible but minimal. Maybe it isn't

depending on what charge is on the medium negative or positive will either atract or repel the water molecules. im not sure which is what though as it was a fair while ago i read into it. i think zeolite has a negative charge which might attract water molecules?? it doesnt sound right but i think that was the go with it.. cant remember now.

jamie

Next time I dunk and weigh the various mixes I will also do a tilt test to see how much water is in a table.

grant

NBPCA wrote:

Grant Bowie wrote:

NBPCA wrote:Hi all,

I will eventually be setting up a trial of diatomite and others as growing media and trying various permutations and combinations of them together.

Firstly we will see how much water the various media absorb/or not and then hold onto/or not.

At the collection I have some brand new orchid pots measuring measuring 28cm accross and 11cm deep. The holes are generous and largish so I will use a drainage layer of equal volume of each type of potting media in each pot.

Weigh first, then dunk and let sit in the water for say 10 minutes, then lift and drain and then reweigh each one as it stops draining, and then all at the same time each hour .

(I will donate the various potting materials that I have accumalated as I will use it all up myself eventually.)

Any other suggestions or observations at this time?

Other suggestions are now 1 Air Filled Porosity, 2 PH, 3 drying out times (but you can adjust by particle size)
Grant

A few more tests to add to the list.

Freeze and thaw test, Sit in water test to see if it breaks down, Amount of water needed to saturate and start draining.

Grant

Tilt test for water table after say 1 hour.

Grant

Just a quick update.

I have got Scoria now to add to the list.
Pumice ordered as well. (Late July)
Also for WA people I am testing the Carnarvon River Gravel as well. I have some bags coming from WA with the order of Akadama/Kanuma.

Grant

I have ordered some bags of Maidenwell Diatomite from Sage Horticultural so I am almost there in regards to gathering the various potting media for my tests.

I will let you all know as soon as it arrives and the tests are done.

Grant

Grant Bowie wrote:I have ordered some bags of Maidenwell Diatomite from Sage Horticultural so I am almost there in regards to gathering the various potting media for my tests.

I will let you all know as soon as it arrives and the tests are done.

Grant

Grant - just a suggestion as I noticed you said the diatomite appeared dry after a few hours but the zeolite still appeared wet. I notice when the diatomite appears dry, if you rub it between your fingers, moisture comes out if it had been watered 24 hours previously. Perhaps this test could be added to your repertoire?

Glenda

Glenda wrote:

Grant Bowie wrote:I have ordered some bags of Maidenwell Diatomite from Sage Horticultural so I am almost there in regards to gathering the various potting media for my tests.

I will let you all know as soon as it arrives and the tests are done.

Grant

Grant - just a suggestion as I noticed you said the diatomite appeared dry after a few hours but the zeolite still appeared wet. I notice when the diatomite appears dry, if you rub it between your fingers, moisture comes out if it had been watered 24 hours previously. Perhaps this test could be added to your repertoire?

Glenda

I will advise on the "look" of each material but the real test is its weight after certain periods. That tells us how "wet" it is. thanks

Grant

Thanks, Grant. I thought about the weight after I had posted. Next time I won't let my fingers get ahead of my brain.

Glenda wrote:Thanks, Grant. I thought about the weight after I had posted. Next time I won't let my fingers get ahead of my brain.

No problem Glenda,

It is important to note and to know both aspects; the look and actuality. Otherwise obvious steps or conclusions can be missed or missed construed.

Something could look wet but not be holding as much water as something else that looks dry. Wet and Dry may infact be too simplistic a term. Feel may be more appropriate?

I will consider this when putting together the results.

Grant

We have begun.

Grant and Leigh