Asked in GardeningSoil
How long does it take to form one-inch of top soil?
June 23, 2009 11:39PM
It depends on where it is forming, natural geology, climate, etc... but it is considered a non-renewable resource because on average it takes 100 to 500 years for 1 inch of topsoil to "grow."
It is also interesting to note it grows downward as the rock breaks down, not upwards as one might imagine.