Lighting 102

LEDS, HIDS & ADVANCED LIGHTING TECHNIQUES FOR ADVANCED RESULTS

Once you understand how lighting is measured, what types of lighting exist, and how to evaluate the quality of your lighting; you can begin to understand your plant's lighting needs on a more advanced level and accommodate them using advanced techniques, setups, and cycles.

• Watts (w) - A Watt is a unit of power. Traditionally, input wattage was equal to the output of the light. In LED systems, equivalent wattage ratings are often used, but the actual wattage is based on the input.

• Photons - Light particles received by plants as energy used in photosynthesis.

• Photosynthetic Active Radiation (PAR) - Refers to the visible spectrum of light (wavelengths within the 400-700 nanometer range) that power photosynthesis. PAR is not a unit of measure but rather a type of light on the spectrum that supports photosynthesis. The amount and quality of light are the most important factors.

• Photosynthetic Photon Flux (PPF) - The total PAR in a system that is produced per second. The higher the number, the better.

• µmol/micromol - A measurement of photons within the visible spectrum of a plant that trigger photosynthesis. The higher the measurement, the more photons present in the system.

• Daily Light Integral (DLI) - A measurement of how much PPF is needed daily for your particular crop. This measure varies with different agricultural zones.

In recent years, there has been a significant amount of information produced on the nuances of lighting and the various ways to finesse the balance between spectrum and intensity (ppfd)—and how to deliver the proper ratio of both for perfect photosynthetic response in plants.