These are the fundamental principles of greenkeeping, if one agrees that greenkeeping is all about the growth rate of the grass and modifying that rate to get the desired surface conditions. Here’s what influences the growth rate, how turfgrass managers can think about those factors, and how they can be adjusted to achieve the desired growth rate. Every turfgrass manager knows that temperature, light, water, and fertilizer will influence the growth rate of the grass. Because the growth rate, and adjustments to it, are what finally produce the desired playing surfaces, it is critically important to understand how these factors can be adjusted. This book explains how the influence of air temperature, photosynthetic light, plant water status, and leaf nitrogen content can be thought of and communicated as a grammar: the fundamental principles or rules of an art or a science.