People are too busy with their everyday lives to notice the grandeur of God in each and every corner of the natural world. In their ordinary, workday existence, they treat nature as an object—something to be worked, exploited, and manipulated for man's own benefit. This is what Hopkins is driving at when he says that "[A]ll is seared with trade; bleared, smeared with toil."
The ground beneath our feet has become purely a place of work, such as plowing and sowing. It no longer has the sacred significance it once had. Modern man has forgotten that this is God's creation and that his divine spirit permeates every feature of the natural world. Hopkins laments this attitude towards nature, wondering why men no longer "reck his rod," i.e., why they don't pay heed to God's power.
Yet despite our treating God's creation so very badly, God still remains buried deep within his creation:
[N]ature is never spent;
There lives the dearest freshness deep down things.