|Purple LED Lights|
|Full Spectrum LED Lights|
Light-emitting diodes (LED) are attractive because they do not require ballasts and they do not emit as much heat so can be placed close to crop surfaces. They can also be placed in an array, and the hue can be controlled by varying the intensity of individual colours of LEDs. Initially, manufactures targeted the red and blue spectrums of light because it was thought to be more efficient to put the energy into the wavelengths that are absorbed the most.
|Red and Blue light are absorbed the most by Chlorophyll|
Full spectrum LED lights are now available at very reasonable prices making them the go to choice for many growers. NASA for example determined that LED lights are the best single source of light for growing plants.
Other Common Plant Lights
HID - Pros: high penetration, full spectrum (HPS and MH); Cons: high heat and energy use, requires ballast
Florescent - Pros: low initial cost, low energy use, low heat; Cons: performance decay over time, low penetration, requires ballast
Induction or Plamsa - Pros: long life, no performance decay, lower heat; Cons: expensive, requires ballast