Understanding Turfgrass Growth Regulation
Plant growth regulators (PGRs) have been applied to turfgrass since the late 1940s. Growth can be defined as irreversible enlargement in size, while development is the transformation of apparently identical cells into diversified cells and plant organs. Based on these definitions, turf PGRs can be divided into two basic types: type I growth regulators and type II growth regulators. Equipment such as single- or multiple-flood jet nozzles, raindrop nozzles, the Lesco Gun, and hose-end sprayers all work best for soil-targeted chemicals. Equipment types available for foliar targeted products include flat fan nozzles or the ultra-low-volume applicators such as the Expedite System. Foliage-targeting equipment can work well for soil-targeted or root-absorbed chemicals providing irrigation or rainfall washes the chemical down to the soil within a reasonable time. A most important step in understanding where to use growth regulators is to classify the areas according to level of management.