“Regulating plant growth” means the use of any substance or mixture of substances intended, through physiological action, for accelerating or retarding the rate of growth or rate of maturation, or for otherwise altering the behavior of plants or the produce thereof.
However, it shall not include the use of substances to the extent that they are intended as plant nutrients, trace elements, nutritional chemicals, plant inoculants, and soil amendments.
Also, “regulating plant growth” shall not be required to include at all the use of any of such of those nutriment mixtures or soil amendments as are commonly known as vitamin-hormone horticultural products, intended for improvement, maintenance, survival, health, and propagation of plants and are not for pest destruction and are nontoxic, nonpoisonous in the undiluted packaged concentration.