In the formal language of economics, X and Y are substitutes if the demand for X increases when the price of Y increases, or a positive cross elasticity of demand.
Potting mix is the material that goes into a garden pot before you put seeds and plants into it. 1  It keeps the plant in place. 2  It holds water for the plantâs roots to soak up.  It contains nutrients that feed the plant.
Hot Mix. The best way to fix potholes is hot mix asphalt patching. Hot mix is the more permanent fix and thus the cheaper long-term option. Asphalt Patching in Maryland. PTG Enterprises has been in the asphalt paving, concrete, and masonry business for more than a decade.