Soil at a new house in Seattle
My wife and I are buying a new house in NE Seattle. One of the cool things about the new place is that the front hard is a few feet below the street, and adjacent to the (not busy) street there is are three levels of terraced beds made from poured concrete, maybe around 300 sq ft. We really want to plant some ornamentals next to the street and vegetables on the bottom two terraces.
Right now, the soil in there terraces is some kind of hard grey stuff a fair amount of gravel in it. I assume the previous owner bought this stuff somewhere since it does not really look like native soil. I was wondering, does anyone know what this is? Is it just the cheapest fill dirt he could find, or might it actually be OK for growing stuff?
I am prepared to till it and remove it with a grain silo scoop in order to replace good topsoil in there. How much of it do I need to remove and replace with "real" soil in order to have a decent garden? If I leave it as a subsoil under a top layer of good topsoil, should that be OK?
Thanks for your help!