PGR

A plant growth regulator (PGR) is a naturally occurring or synthetic compound applied in small quantities to influence a plant's growth, development, or physiological response, rather than to supply nutrition the way a fertilizer does. PGRs work by mimicking, boosting, or blocking a plant's own hormone signals — gibberellins promote stem elongation, seed germination, and fruit set; triazole-based retardants like paclobutrazole do the opposite, inhibiting gibberellin synthesis to produce shorter, stockier growth and encourage flowering over vegetative spread; and biostimulant-type inputs such as humic acid, seaweed extract, and amino acid formulations support root development and stress tolerance indirectly, through soil and plant-health effects rather than a single hormone pathway. Because PGRs act at such low concentrations and different active ingredients push growth in opposite directions, matching the right PGR to the crop's growth stage and the intended outcome (taller vs. shorter growth, more flowers vs. more foliage) matters more here than in most other agri-input categories.