TimberClean Pro is an extremely powerful oxygen based weathered wood restorer. When in it´s solution, millions of tiny oxygen bubbles act to deep clean the surface removing UV damaged wood fiber (the gray you see), killing off mold and mildew spores, and restoring the natural color back to your wood. TimberClean Pro comes to you in it´s granular form... you supply the water (why pay shipping on water?)! 30lbs of granular makes 60 gallons of concentrated solution (that´s less than a $1.70 a gallon!). TimberClean Pro is safe to use around plants and vegetation although measures should be taken to prevent the solution from contacting unintended surfaces. We recommend you follow up your cleaning with TimberBright Pro for an additional opening of the pores and brightening of the surface.