Let me get straight to the point. I'm living in Bulgaria and I'm having troubles finding stuff to mix good soil for Chinese Elm, which was gifted to me(as usual the tree for a newbie ). I've read some of the info here and some other articles for soil structure( Harry Harringtons basic guides). I have done some research on what is available as materials for "soil" in my country I would need some advises on what could be used. I do have access to the following materials:
Vermiculite - Manufacturer says it could be used as up to 50% of Bonsai soil
Keramzit - This seems to be a material widely used in the former USSR for insulation. Sold for pot drainage. I think its made from baked clay.
Lava Rocks - They look red-brown, small balls 5-10mm I think widely used in hydroponics.
Pine bark - still looking for it
2 Brands of soil sold as "Bonsai soil":
Brand A - peat, clay particles, sand and crushed keramzite, enriched by basic nutrients and trace elements.(haven't seen an opened bag to know how big particles are).
Brand B - Black peat, sand, clay, lime and nutrients.
Orchid substrate - Natural pine bark, peat and Styromull ( was wondering if this could be used also)
I need to decide what could be used for Chinese Elm particularly, when taking into account my geographical location and the fact that I am living in an apartment with a small western terrace. The new container is 20cm in diameter and 7-7.5cm deep.
Thank you in advance.