The Kelvin Color Temperature Scale is a measurement of discriminating colors for the human eye. Color temperatures over 5,000K are called cool colors (blue/white), while lower color temperatures (2,700?3,000 K) are called warm colors (yellow/white through red). This is a measurement for the human eye, but serves as a reference for helping consumers know which lamp to buy for which stage of growth.
Not all growers are able to buy four lamps for every fixture, so the “one lamp system” means you could use the 4K for all stages of plant growth if needed. Your plants will get photo-chemical reactions with a Lumatek lamp that is more than could be achieved with any traditional lamp that was made for human vision.
HPS – Recommend for the majority of flowering when growing annual plants.
4K – This is a Full Spectrum light good for all stages of growth.
6K – Popularly used for vegetative growth and 3K – 2K; consistently used for flowering and fruiting growth.