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.
1. a product of mixing. 2. any combination or blend of different elements. 3. an aggregate of substances not chemically united and existing in no fixed proportion to each other. 4. a fabric woven of yarns combining various colors: a heather mixture. 5. the act of mixing or the state of being mixed.