LED Grow Light BasicWe’ve been waiting a long time for garden lights based on light-emitting diodes (LEDs) to make it to “prime time.” NASA and others have been experimenting with LED grow lights since the mid-80’s, and we are finally starting to see products reaching the market that reflect their findings. These lights represent a major step forward.
LED grow lights offer the dual benefit of low energy consumption and low heat generation. Some LED grow lights use so little electricity that they can be powered by a small solar panel. According to their manufacturers, today’s LED grow lights consume between 2% and 50% of the electricity used by the HID grow lights they reportedly replace. We’ve yet to see in real-world application whether these lights will perform as well in the garden as those “comparable” HIDs, particularly for high-light crops.
LEDs, short for Light Emitting Diodes, are tiny semiconductor chips that generate light when electrified. It takes a small amount of electricity to make an LED glow (emit electrons), and the elements that the diode is made from determine the light spectrum it emits. An LED is backed by an internal reflector and encased in an epoxy body with an integrated lens. Together, these components determine the angle of the light emitted by the diode, which is shaped as a downward-facing cone. Individual LEDs produce relatively small light cones, so they are clustered into arrays so the light cones overlap, increasing light intensity and coverage area.
LED grow lights are designed to stimulate photosynthesis by providing light in the frequencies that plants primarily use for this critical biological process. Individual LEDs may contain one of 29 known combinations of elements that emit light in different colors when excited by electrons. Grow light manufacturers emphasize blue and red LEDs in their fixtures, sometimes with other colors, which gives many LED grow lights their distinctive purplish-red color. Optimizing the light spectrum helps in two ways: it enhances photosynthesis and saves energy by not generating light in colors that plants do not use.
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