Grow Lights: What is Kelvin (K)Temperature?

November 30, 2018

Kelvin temperature is used to describe the visual color of light that a lamp emits. Technically, it is a measure of how white a piece of tungsten steel is when it’s heated to a specific temperature in degrees Kelvin. A lamp with a Kelvin measurement of more than 5000 Kelvin (K) produces more light in the cool blue spectrum.

These fluorescent grow lamps have a 6500K rating, for a cool-colored full spectrum light.
PC: Leslie F. Halleck

Lamps with a lower measurement, in the 3000K or lower range, produce more light in the warm red spectrum. Kelvin temperature is not a measurement of actual hotness or coolness of the lamp, but rather the visual temperature of light, which can have a big impact on how your indoor space looks.

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