Specialty Gardening: Container Soils and Water Movement in Containers (long post), 1 by tapla

tapla wrote:
I use Miracle Gro 12-4-8 liquid fertilizer at 1 capful per quart once per week (in a fast soil that drains freely). Cut the dose by half if you use a bagged potting soil. I also supplement with a little Epsom salts every so often (probably every other week, I'd guess) when I think of it.

Turface is a calcined (high fired) clay that is ceramic-like. It's very air and water porous & holds water & nutrients very well (excellent CEC). One pound of Turface has 13-1/2 acres of surface area. It's an excellent soil amendment, used extensively on athletic fields & golf courses because of the properties listed. Additionally, it adds porosity to soils, promotes drainage, and is extremely stable. See Turface at lower left & crushed granite at lower right.

The dark soil at the top is a soilless blend I have in all my raised beds.

Al