light bulb question. easy

So when people talk about lights I see stuff like 6500k what is this?

K Means Kelvin and it mesures the color temperature! 5000K and more we call them Cold Colors and it's mosetely (blueish white) while lower color temperatures (2,700–3,000 K) are called warm colors (yellowish white through red).

CFL growers refer to there numbers in order to get the right bulb spectrum for a particular plant cycle or to get a full spectrum by combining 2 or more lights.

Do a search for kelvin in that box at the top of the page. You will find everything you need. Peace

6500 K is good for vegging and 2700K is best for flowering, however you can use a combination of both during your entire grow. I use to grow with CFL's and that's what I did and it worked great, always grew dank bud.

Color spectrum, color spectrum, color spectrum.

Thanks guys!

Ganja home gave a nice thorough, concise explanation of exactly what it means and how we use it.