The Watt Myth in Grow Lights

Many grow lights are still marketed mainly by wattage. It sounds simple: more watts, more power, better light. But for plants, this is not enough. Watts only describe how much electrical power a lamp consumes. They do not automatically tell you how much plant-relevant light actually reaches the plant. In professional horticultural lighting, other values are more important: PPF describes how many photosynthetically active photons a light source emits per second. PPFD describes how many of these photons arrive on one square meter of plant surface per second. These values are much more meaningful for plant cultivation than watts alone. The efficiency of a grow light is also not measured seriously by watts alone. What matters is how well electrical energy is converted into usable plant light. This is commonly described as photosynthetic photon efficacy, or PPE, measured in µmol/J. The higher this value, the more plant-relevant photons are produced per joule of energy. For FLORIQ, this means we do not think of plant lighting as “as many watts as possible.” We think in terms of usable light on the plant surface. That is why PPFD, light distribution, distance, number of sticks and dimming are more important than a simple wattage number. An efficient lamp is not automatically the most powerful lamp. An efficient lamp delivers the right light where the plant needs it.