Some grow light systems might provide good PAR control, but if their optical configurations are weak, the amount of quality light that reaches the plant surfaces will be equally weak, particularly due to the wasteful light loss of undirected beams scattering into the aisles and across the wall. The engineering that separates a high quality LED grow light from the knock-offs is the application of advanced optics. In order to take full advantage of the light your fixture is producing (and the energy it’s consuming), the optics need to focus the entire beam toward the crop without waste or sloppy spill.
To verify that plants are getting sufficient quantities of PAR-optimized grow lighting, cultivators can measure PPF and PPFD at several locations throughout their facility. LED grow lighting systems, for example, can have high PAR ratings directly in front of a fixture, but that rating will drop significantly as measurements are taken at oblique angles or in the lower canopy of the crops. If your fixture isn’t taking control of the beam and directing 100% of the PAR onto the surface area of the plants, you’re wasting energy and the yield will suffer.