How far should CMH lights be from plants?
Ceramic Metal Halide Grow Lights CMH lights were introduced in the 1980s, but with recent discoveries in horticulture research, it makes sense why many growers are utilizing this technology.The CRI of CMH's is around 90-92, close to the spectrum you get from the sun .The claim from CMH lovers is that your plants can enjoy a nearly full spectrum white light, very similar to natural sunlight that lasts longer than your HID counterpart. A CMH's Color Rendering Index (CRI) rating is pretty close to the sun. CRI is a measurement of how true colors stay when the light is set upon them. HPS grow lights are 20 - 30 (that's why it's all orange/yellow in your grow room during flowering) while Metal Halides are 60 - 65 (which is why there's a little bit of a blue tint in your growing area when you're vegging). CMH grow lights come in with a CRI rating of 90 - 92 making them only 8 points off from our most natural source of light. Right off the bat, once you turn on ...