bonsapien wrote:What is the best size for crushed lava?

The "best size" for soil particles for your trees depends not only on the size of tree and pot, but also on the water requirements for your tree, its stage of development, etc.

For water lovers like Japanese black pines and trident maples, I use 1/4 - 3/8 inch mix. For trees that need less water I use up to 1/2 inch particles. That way I can water everything at the same time and the ones with smaller particles keep more water.

Chris Johnston wrote:
The "best size" for soil particles for your trees depends not only on the size of tree and pot, but also on the water requirements for your tree, its stage of development, etc.

For water lovers like Japanese black pines and trident maples, I use 1/4 - 3/8 inch mix. For trees that need less water I use up to 1/2 inch particles. That way I can water everything at the same time and the ones with smaller particles keep more water.

I assume it would be safe to say that you do not use 1/2 inch particles on trees that need less water, if they are Shohin or Mame?

Many people use different techniques, personally I control water retention with the soil components, in example more water retaining material for wet loving trees and less for dry loving trees. I let the container size dictate which size of particles to use, this also, as a side effect, lends a better sense of scale to the whole. Of course many people hide this with a fine soil covering, but I find that this ultimately defeats the purpose of the larger particles, as the finer material will work its way in between the larger.

If you shift your components, you will find a use for every size sorted, including the fines which can be used for muck or as Mame soil.

As a general rule, small particles for small trees, large particles for large trees.



Will

Chris Johnston wrote:....But inorganic soil with organic fertlizer promotes mycorrhizal growth....

Yes, when you add organic...this takes it from the inorganic reference I used. When you add organic material to the soil, it is no longer inorganic.

The answer to the question I asked you ("what do mycorrhizal mushrooms feed on?") is organic material, considering such it is quite easy to understand that "Micorrhizae grows much slower in a sterile inorganic mix and in many cases, not at all."


Will

Will Heath wrote:

Chris Johnston wrote:....But inorganic soil with organic fertlizer promotes mycorrhizal growth....

Yes, when you add organic...this takes it from the inorganic reference I used. When you add organic material to the soil, it is no longer inorganic.

The answer to the question I asked you ("what do mycorrhizal mushrooms feed on?") is organic material, considering such it is quite easy to understand that "Micorrhizae grows much slower in a sterile inorganic mix and in many cases, not at all."


Will



Will

So you are saying my understanding of the articles and definitions in question is completely lacking?

[quote=Colin Lewis]One party to this relationship is your tree, the other is a microscopic beneficial fungus. The fungus forms a sheath-like structure at the root tips through which it passes to the tree various nutrients it has gathered from the soil in exchange for food the tree has produced through photosynthesis (remember, fungi are not able to produce their own food in this way).[/quote]

Wikipedia says something similar,

This mutualistic association provides the fungus with relatively constant and direct access to mono- or dimeric carbohydrates, such as glucose and sucrose produced by the plant in photosynthesis.[2] The carbohydrates are translocated from their source location (usually leaves) to the root tissues and then to the fungal partners. In return, the plant gains the use of the mycelium's very large surface area to absorb water and mineral nutrients from the soil, thus improving the mineral absorption capabilities of the plant roots.[3] Plant roots alone may be incapable of taking up phosphate ions that are immobilized, for example, in soils with an basic pH. The mycelium of the mycorrhizal fungus can however access these phosphorus sources, and make them available to the plants they colonize.[4]

I could be wrong, but it seems to me that one type of fungus breaks down organic material for its nutrients, and the other gets carbs from the plant itself rather than break down organics. If I'm wrong, I'm wrong, and it won't hurt my feelings. Something doesn't seem to add up.

As to soil size, perhaps you missed my first clause, "In addition to pot and tree size,..."

Good article. I think I'll be trying spagnum instead of pine bark in my mix and see how that goes. I suppose I could just chop up the long fibered stuff and add it to the mix?


Tom

Tom, any sphagnum moss will pretty much work. However, as with most things, some preform better than others. I have found that Angel Moss, aka New Zealand white sphagnum moss (sphagnum christatum) works exceptionally well far out performing most bagged stuff you find at garden centers.