Maximum Yield USA September 2017 | Page 86

tips & tricks S uccessful grow lighting begins with a carefully considered light plan. A light plan calculates the best possible coordination of luminaires in terms of their distance and orientation from one another, as well as the crop. The trick lies in determining the ideal combination of these factors to ensure that you will achieve optimum light yields—with as few fixtures as possible WHAT COMBINATION IS BEST? The accuracy of the light plan depends on a thorough analysis of several factors—including the desired light level, the light distribution, the most effective mounting height, environmental conditions, and the construction of the growing facility. The target light level (at the crop canopy) should always be the starting point of any light plan. All the other factors that will affect the layout and performance of the lumi- naires should be considered to determine how to achieve the desired light level with optimal uniformity and efficiency. These factors include: • The dimensions of the grow facility , with the most critical dimensions being the length, width, and ceiling height of the space—as well as the anticipated finished crop height. These dimensions will be used to establish the number, spacing, and orientation of luminaires required. The anticipated crop height is important in calculating the available distance between the mounted luminaires and the surface of the crop canopy. This distance will determine what luminaire and/or reflector will deliver the optimal performance in that particular application. For a facility with a low ceiling height, for example, a low-profile luminaire—that is, designed for optimal thermal management—will allow for a greater distance between the light source and the crop. Similarly, a reflector that delivers a wide distribution of light can enable growers to achieve optimum light intensity evenly across the surface of the crop with fewer luminaires. TIP (W) (M) (L) 84 grow cycle WHEN CALCULATING THE ANTICIPATED CROP HEIGHT, DON’T FORGET TO FACTOR IN THE BENCH HEIGHT. Width of room Desired mount height Length of room (H) Height of ceiling (C) Anticipated finished crop size, floor to canopy