Hi,

As far as green plants are concerned, they love intensity but they only respond to certain wavelengths (or colours). They thrive on red/orange and blue/violet light but they reflect green light (hence the plant appear green to us).

Since it is much cheaper for us to buy high intensity red/orange (aka low kelvin lights) lights than it is to buy high intensity purple (aka high K), I believe low kelvin lights are the best solution.

Broad spectrum daylight isn't bad for plants, its just not ideal. Its light is balance. It may not have a strong red/orange or a purple component. Since high and low kelvin lamps may have a stronger component in those regions, these lights will do better than daylight.

Its all IMHO of course :D

- Victor.

I know heavy in the red spectrum will encourage one type of growth and high in the blue will encourage another type of growth but I had never heard they reflect green, as everything i have read is that all light between 385nm and is it 720nm us usable for photosynthesis. and the key is trying to get the right blend.

Oh isn't the red spectrum for fast spindly growth while the blue promotes good root development and budding?

I think overall unless you are running a indoor grow op you are not going to notice a difference or a lack of performance using a daylight bulb.

Steve

i'm using a 13w 2600k bulb... and my macro is doing pretty good.
I think if i increased the wattage that it would grow quicker...

I was skeptical about the 2600, but apparently its working...

you should run 6700k bulbs for fuge growth. higher the wattage the faster the growth.

I think you should try the 4100k bulbs for the mere reason nobody has mentioned this tempurature yet! :D

To eleborate on steve's comment:

2700k "RED" spectrum (similar to HPS), for general growth and blooming.

6500k "BLUE" spectrum (similar to Metal Halide), for seedlings, cuttings, and clone growth.