My new home has a nice little walled garden area that I’ve slowly been turning into a work area for my trees and other gardening habits. It’s got a concrete floor, but one corner has a 10’ x 10’ area of plain ol’ soil, where a cedar tree used to live many decades ago (I just removed the old stump last weekend, or rather, the leftover fatwood that was under the soil).
I’d like to use this are to plant trees for “field-grown” development in between pottings. Does anyone have a suggestion for the type of soil amendment I should make to optimize conditions? Should I plant the trees like I would normally set a landscape specimen, but backfill the hole with bonsai soil? Should I just use plain ol’ topsoil, or some other?