Posted: 30/08/2012 at 21:38
Every inch of our garden contains bits of coal and in places it is almost pure cinders. The Veg gardens have the least coal and no cinders, and we have had no problems so fat in 20 years of eating.
Be glad your garden does not have our major contaminants.......hundreds of batteries from the old accumulator types with lead plates to modern torch batteries. We had to put the Veg areas where there was the least number of these things.
I think the clay residue is possibly from the coal fires.