DIATOMITE ??

[buddaboy]

Zeolite kills my figs! 4mm sieved zeolite and my figs rotted in four weeks. Far too much water, I get better results using straight unsifted potting mix. Not out of a book or from a website, but actually seeing my figs wilt.

Here endeth the lesson.

buddaboy

[kcpoole]

Zeolite kills my figs! 4mm sieved zeolite and my figs rotted in four weeks. Far too much water, I get better results using straight unsifted potting mix. Not out of a book or from a website, but actually seeing my figs wilt.

Here endeth the lesson.

buddaboy

Thats Weird Bubba.
I have All of my figs in My diatomite mix ( 2/3 Diatomite, 1/3 Zeolite) and they all thrive.
I have had figs in this mix for 4 years now, and have this past summer repotted all my remaining ones into it.

I water Every morning thru summer, and on the hot days > 35C will do so again in the late arvo. In winter id every second day.
I have not had any problem with them staying too wet, and has been said that Zeolite and Diatomite will hold the same amount of water as each other and any more will just run out of the pot.

Ken

[craigw60]

Mojo is spot on its the air spaces between the components that counts, allowing the roots the breath is so important. As I said in an earlier post pre diatomite I used granite and if there was no granite around I used blue stone the important thing is to open up the mix so air can circulate around the roots. This is also the reason its vital to allow your trees to dry out before watering.
Craig

[Joel]

There are different zeolites. Buddaboy, was your zeolite soft? Could you break it with your fingers at all or mark it? The stuff we use in Sydney is really hard. Its like quart but red.

The things we are concerned about are:
W.H.C. - Water holding capacity
C.E.C. - Cation Exchange Capacity
Particle size.

The W.H.C. of the zeolite i use is DEFINITELY lower than that of the diatomite i use. Succulents and cacti would do well in 100 percent zeolite. Some plants might do OK. But a majority wouldn't survive my micro-climate at home in pure zeolite. They do, however, in 100% diatomite.

The C.E.C. in zeolite is far superior. It holds far more nutrients than the diatomite. And contrary to what Jamie said, it does NOT lock them up and make them unusable. The key word being cation EXCHANGE. This means they hold the ions and swap them when they are needed. The plant is definitely capable of using these ions. Why do people always add O.M. (Organic matter) to soils in gardens? The answer is humus. Humus is what is called a colloid. Colloids have high C.E.C. And as Brett also knows, humic acid works the same.

With porosity, you have macro and micro pores. In the case of this two relatively large particle substances, the macro pores are the spaces between each particle, and the micro pores are the holes withing the structure. The diatomite i use has slightly larger particles, which means larger macro pores but less of them, and a smaller surface area. This doesn't really matter as its micro pores still provide sufficient moisture. This means it is getting more air whilst not drying the roots. But both are of sufficient size so that you will not get anaerobic soils.

Basically, Kens mix (2/3 diatomite to 1/3 zeolite) combines the high W.H.C. and porosity of diatomite with the high C.E.C. of zeolite. Alternatively you could go for the organic colloids and use O.M. or you could not worry about the effects of leaching and just fertilise more regularly.

Either way, both diatomite and zeolite have useful properties. They are great products.

Joel

[Bretts]

Hi Joel. Considering the salt intolerance of the hornbeams it was suggested that Zeolite might be holding onto the salts (Nutrients) with it's high CEC and we may be better off not using it for our hornbeams.
Would you have any thoughts on this?
Edit: these are the values of CEC a google search gave me.

SOIL TYPE CEC
Sand 5-20
Akadama 21
Clay 20-50
Organic Soil 50-100
Diatomite 40
Zeolite 120

[Joel]

Hi Brett,

I think its unusual akadama has a C.E.C. that low. Would have thought it would be the same as clay. That's interesting.

I don't know about the hornbeams soil. I know that most carnivorous plants hate salt and so people use sand and peat moss. The peat moss (Sphagnum peat) is very low in salts, and the low pH locks up salts too. That is why carnivorous plants evolved to be. They had no nutrients. But salts ARE the nutrients. Do you fertilize them regularly? Have you had problems with salt burn?

Joel

[Bretts]

Yep Joel I am sure my leaf burn issues on the hornbeam are a salt intolerance problem. Remember our discussion on the chemical/organic fertiliser Might leave the Zeolite out for now just in case

I was suprised by the CEC values as well the first 4 came from the old BT Wiki

[Grant Bowie]

Has anyone done any comparitive tests on the actual water holding capacity, side by side, of Diatomite/Spongelite/Attapalgite vs Akadama vs Zeolite vs Perlite etc (I would also include crushed brick here as well) ?
Anything "gritty" that is sposed to have water holding properties.

Grant

[Bretts]

Discussing this the other day I was thinking about it Grant. The tests I have seen on this seem a little complicated to me.
I was thinking getting several pots of eaqual size for each medium.. Get 1L in a watering can for each pot, water the pot collect and measure all that drians out after say 1 hour and compare each one.
That should be a realistic test of what each medium is soaking up.

You would need to be vigilant with the sifting and grading of the mediums.
You should have a control of an empty pot as well

[Grant Bowie]

Discussing this the other day I was thinking about it Grant. The tests I have seen on this seem a little complicated to me.
I was thinking getting several pots of eaqual size for each medium.. Get 1L in a watering can for each pot, water the pot collect and measure all that drians out after say 1 hour and compare each one.
That should be a realistic test of what each medium is soaking up.

You would need to be vigilant with the sifting and grading of the mediums.
You should have a control of an empty pot as well

Yes, that was the next question. If we do a test we need to control it.

I have Akadama, crushed brick but no Diatomite. I am trying to source some now.

Grant

[kcpoole]

Discussing this the other day I was thinking about it Grant. The tests I have seen on this seem a little complicated to me.
I was thinking getting several pots of eaqual size for each medium.. Get 1L in a watering can for each pot, water the pot collect and measure all that drians out after say 1 hour and compare each one.
That should be a realistic test of what each medium is soaking up.

You would need to be vigilant with the sifting and grading of the mediums.
You should have a control of an empty pot as well

Yes, that was the next question. If we do a test we need to control it.

I have Akadama, crushed brick but no Diatomite. I am trying to source some now.

Grant

Grant are You coming up to Bonsai on the harbour? If so I can give you some if you want. Or Give to Leigh to bring back for you?

Let me know

Ken

[Gerard]

Rather than trying to measure what drains out we could consider "weight" dry, immediately after watering, 6 hours after watering, a day, 2 days.
This would give a better indication of the ability of each medium to hold water.

[Bretts]

Hi Gerard, this is something that is fairly misunderstood. When you water bonsai the medium will drain a certain amount considering what is soaked in by the medium and the water tension that holds the water in between the medium. Then it will STOP! Water tension and gravity find a balance and all the water there will remain until the tree uses it or it evaporates. From what I understand evaporation is minimal.
Oh unless you tilt the pot which again changes the water tension gravity balance.

This is evident with my indoor bonsai. I can water them let them drain and then place them on furniture with no protection from water drainage because after it drains it drains no more. Whether it be several hours or days.

You could do the weight test if you like but like I said I found that complicated swapping from volume to weight and back to volume again. I can't see any disadvantage to using volume all the way?

[kcpoole]

Found this for a little introduction to water holding capacity
http://bettersoils.soilwater.com.au/module2/2_1.htm

Brett you were describing Gravitational action of the water and soil

Ken

[kcpoole]

The best process to measure the holding capacity of water, may be

Fill Sevaral (same type) containers / pots with dry soil ( I have read it shodu be baked in an oven for several hours to ensure it is dry).
Weigh each Sample
Completely Submerge the Pot in water for 10 mins or so to ensure fully wetted thru
Remove from water and allow to stand on a Grate for 10 mins until all water stops flowing
Weigh each Sample again and determine the weight of water held in the mix. You can then obtain the volume of water too

place all Samples in the same environment and allow to dry out at the same rate
Every hour, reweigh the samples to determine the rate at which the amples will dry out
Repeat several times and average the results

Note that this will not give any info re the ability for differeing plants to extract the free water from the various mixes, and I do not knw if woudl be different anyway?

Ken