Indoor growing operations have soared in recent years in part to the burgeoning cannabis market but also the demand for fruits, vegetables, and plants of all kinds to maximize yield. This has put the battle between light sources under the microscope. High Pressure Sodium (HPS) has led the way for years but the technology behind the LED has led to an insurgent charge to the top. How has it happened?
Ultimately growers seek to optimize the growing operation in hopes of increasing total yield and lessening risk and total cost. Most are aware that high pressure sodium fixtures are energy hogs, although an equivalent LED uses plenty of watts as well. But one of the biggest factors in favor of the LED is heat production. The LED is able to apply higher light levels to plants with around 66% less radiant heat compared to the HPS. High levels of radiant heat will stress out plants and potentially burn them out. The ambient temperature decrease also results in massive HVAC savings.
Technique and controls also matter. This is where vertical farming and LED interlighting come into play. With high-wire crops such as tomatoes, the light level decreases rapidly as you get to the bottom of the crop. Interlighting provides better distribution to these lower leaves, allowing them to maintain production levels relative to the rest of the crop. This is much easier to attain and control with new LED fixtures and modules. Overall this contributes to a more efficient process with higher plant density, more vital leaves and a higher efficiency in light utilization.
Vertical farming has been able to take off due to the flexibility of LED. A vertical setup has a higher setup and cost to operate, but it maximizes production per unit of a given growth area and as a result is used in the most advanced greenhouses. Growth conditions need to continually be analyzed to ensure they are running optimally. Controls such as sensors play a part in making sure the LED light is optimized.
For a sensor to be effective, it is important to grasp what data is useful to the growing operation. This includes the light level and spectrum (as perceived by plants) in addition to plant temperature, climate and plant morphology. Sensors monitor these growth conditions, aiming to recognize any abnormalities and identify these problems early on, allowing the necessary changes to be made. Having an initial light plan is important, but being able to pivot and measure the effectiveness of the LED lighting setup in the actual application holds value as well.