Vermiculite and perlite?

[Tinmonkey]

I was hoping to find some info on the use of either vermiculite or perlite in potting mixes for various species but cant seem to find any after two hours of searching.
So my question is, does anyone use either and what quantities for what species?

[stymie]

Both are good mediums for growing seeds in a wind free environment but being light in weight, they don't hold trees upright in wind. They should therefore only be used as an additive to open up the medium. They do not have any feed value.
For guidance on potting mixes, it is useful to know what variety of tree is being considered and its geographical location.

[bonscythe]

Hi,
I use about 10-20% perlite (species dependant) for drainage/aeration purposes, it's much lighter than crushed granite or gravel and can hold 5 times it's own weight in water, similar to how zeolite can trap molecules in it's structure.
And the % of vermiculite I add to a mix depends on how moist the tree needs to be. It does break down a bit over time I have noticed so I don't use much, might be better to stick with coco-peat or whatever your currently using for moisture retention.
50-50 mix of perlite & verm is a good cutting-raising mix though, and as stymie said it is great for seed raising too.

[Tinmonkey]

Thanks for the replies guys.
I had originally bought some for propogating cuttings and had some left over.
I was concidering doing a repot of a collected casaurina into a grow box to get some nebari happening. It already has amazing taper. I want to concentrate the growth in the roots so I was thinking of using the rest of the vermiculite and perlite with a fairly large agregate into the mix to give a pretty airated root environment and then feed accordingly.
Am I on the right track?