I have some older CFLs in my grow room. When physicaly looking at the bulbs, the older bulbs are a real red orange, the newer CFLs are a yellow white, same wattage and brand, just a few have been used around my house for years. My "full spectrum" 5K CFLs seem to lose their blue, and seem more "white" Any one have a theroy? We know total light output is reduced, but what happens to the kind of light they produce?
Think of it like the stars. They only burn hot for so long, when the temperature changes the color changes. If it seems like you get better plant growth with a dying bulb, then I would say you probably have a heat issue, either the light is too close or too high wattage for application or lack of ventilation.
Run high kelvin bulbs (6500k) for veg, and 2700k for flowering. A mix of the 2 can be used successfully as well, with the mixture leaning more toward veg or flw for kelvin purposes. Sent from my SCH-I545 using Grasscity Forum mobile app Oh, and change your bulbs out about once a year. Sent from my SCH-I545 using Grasscity Forum mobile app