Light Intensity

HOW DISTANCE AFFECTS RESULTS

The inverse-square law states that the intensity of light radiating from a point source such as LED, is inversely proportional to the square of the distance from the source. This means that an area (of the same size) twice as far away from a light source at full intensity, receives only one-quarter of the energy as shown in the image to the right. As distance continues to increase from the source, light intensity subsequently decreases.

The most popular methods of measuring light intensity are expressed in units of lumens or PAR. Lumens express how intense a light source is to the human eye, while PAR expresses how intense the same light is to plants. HID manufacturers have been confusing people for decades by rating their products in lumens, when this has nothing to do with photosynthesis or quantum efficiency. So while a 1000W HPS may emit 145,000 lumens to the human eye, the PAR (photosynthetic) value they emit at 12" is roughly 2000 micromoles, which is equal to the sun on Earth. Therefore, when comparing HID to LED, the only reading that matters is micromoles.

Light Intensity is determined by 2 factors: the total light output from a source, and how it is dispersed over an area. Our GS600 grow light produces over 2000 micromoles at 12" from the glass, rivaling the output of a 1000W HPS! Our incredibly intense 3W LED's are what enables us to achieve this level of output, and flower plants with the same vigor of a 1000W HID. The second part of the intensity equation is light dispersion, which is controlled by the emitting lens on each LED. Most of our competitors are still in the dark ages with their wide-angle 120 degree lenses, but not Grow Stealth. As seen in the second image, 120 degree lenses have over 2x less intensity than our 90 degree lenses, as they try to disperse the same amount of light over too large an area. It goes without saying that when it comes to light intensity, Grow Stealth products are miles ahead of the rest!