survey: the best .....

Hi all,
I know that from time to time different members here asking and posting about "the best soil for bonsai". of course this is very hot topic
for us. but as you already know, and correct me if I am wrong, most of our trees are not a bonsai, rather than "developing bonsai"
or "in training stage". as we all know, there is a difference between the characteristics of bonsai soil, and developing bonsai soil. for instance we expect from a bonsai soil to limit the growth of the tree, and from a developing bonsai soil we expect to accelerate it, etc'.

so, my question is, upon your experience and knowledge, what is the best soil/soil mix for developing tree in container ?

thank you all

Efi

the trees development require draining soils, grains with big size, very airy, a lot off water, sun, hygrometry , in the box, but also around the box and the tree, an important fertilizer (organic fertilizer with chemical fertilizer) , humics acids .
The box or container should be large, airy (plastic grids at the bottom and on 4 sides to facilitate gas exchange (when watered, the carbon dioxide emitted by the roots is replaced by oxygen , oxygen is essential for the survival and devloppment of the roots.
Turfcae or pumice or akadama, mixed soils are good

Michael Hagedorn in his latest post has some things to say about turface:
http://crataegus.com/

efishn wrote:Hi all,
I know that from time to time different members here asking and posting about "the best soil for bonsai". of course this is very hot topic
for us. but as you already know, and correct me if I am wrong, most of our trees are not a bonsai, rather than "developing bonsai"
or "in training stage". as we all know, there is a difference between the characteristics of bonsai soil, and developing bonsai soil. for instance we expect from a bonsai soil to limit the growth of the tree, and from a developing bonsai soil we expect to accelerate it, etc'.

so, my question is, upon your experience and knowledge, what is the best soil/soil mix for developing tree in container ?

thank you all

Efi

I re-use a bonsai soil I buy from a dealer.

What's more important is that I sift it through screens to remove the fine particles and the large clumps.

Sorry for TURFACE, it's a mistake, moreover, we don't use this soil in france, only pumice, akadama, volcanic soil .

Really depends on where you are on the planet.

In cold climates they put barks as part of the soil medium, but here in the very humid part of the earth it will decomposed easily.


Here we just use river sand and volcanic cinder. Some used coco fiber but it will also decomposed and tends to clog drain holes with fine screen.


regards,
jun  

Finding that 4 to 5mm, rounded gravel and compost sifted through a 5 mm hole mesh does an excellent job of growing.
The compost is already decomposed, but with use will rejoin as pills of 3 mm. This is seen when re-potting.

The idea is simple, Ms. Iris's mention of the ball bearing effect, air spaces, freely draining and the compost is adjusted for how much moisture is in the soil and present in the atmosphere.

Adding on to the above to a colander / air pot / smart pot and the root growth is maximized.

Will let you know how the experiments continue to go.

Apart from the above, still using a mix of sifted all, builder's gravel [ silica based ] crushed porous earthenware brick and compost.
Inorganic particles are around 4 to 5 mm, drains well and have been doing this since 1980's.
For really fast growing I have growing troughs [ above ground ] around the house.
Later.
Khaimraj

Finding that 4 to 5mm, rounded gravel and compost sifted through a 5 mm hole mesh does an excellent job of growing.
The quality of pumice for example is that the water is in the grains, and the air around , a substrate with two contradictory qualities , drainage and water retention together .
The choice of the substrate also depends of the country where you are living, and 4 5 mm is too small , for a good growing, 8 10 mm .

8 to 10 mm, wow abcd, that is large, the size of the marbles, I have a test tree growing in.
Looks weird as a soil mix goes.
Later.
Khaimraj

What one uses as a substrate for one's Bonsai is very much dependent on where you live, how much rain you get, how cold it gets, etc. etc.
It is an individual thing more or less, if you are not sure find someone that lives close to you and has experience in growing Bonsai. There are however some basic fact about soil medium that are true all over.

Some soil facts:
There are two types of granulate, one type that hold the moisture on the outside of the kernel like pebbles, grit, crushed granite etc. all non porous material.
The other that holds the moisture inside the granule, like pumice, Akadama, Kiryu, cat litter etc.

Now a medium of pure grit will dry faster than a medium of pure pumice.
So in mixing those two we can achieve the water retention level we want in our environment.

A soil consisting of large particles will hold less water than a soil consisting of small particles.
This is another way to adjust the water retention level, if we want wetter - use smaller particles, if we want faster drying use larger granules.

Soil with granules of the same size will have more intergranular space than a soil of mixed sizes, the smaller granules will fill the space between the larger particles. I use as much as possible the same grade of particle in my soil medium.

Larger granule have larger intergranular space than smaller granules, so more air in large granular soil.

A shallow pot will hold more water than a deep pot, in a deep pot the water will be held in the lower part of the pot.

These are some facts, if you use them to determine how to get the amount of water retention that you need.

As you might have noticed I use no organics in my soil, it does not work for my trees, but that does not mean that it would not work in you garden.

I like the way Arihato has explained it  

I want to add, that pore size of the particle is also important.  The pores of the particle need to be large enough for fine roots to enter or pass through it.  Zeolite, for example, is very porous, but much to fine to allow roots to take up the held water, the smaller the pores, the tighter the water is held. Perlite and pumice has large pores and allows roots to penetrate the particle, thus the water is available for the plant.  So some kind of disticntion has to be made, even for porous components.

Paul

p.s. I grow all my trees in the same mix.