red and blue lights....

Excuse my ignorance, but, I am under the impression that for vegging you can use all blue light, (I'm doing LEDs with a little help from 'daylihgt' 42 w CFL,) and for flowering you can use only red light. During these two cyles other light spectrums are useless????

I'd use a mixture of red and blue, lean towards more blue for veg, have more red for flowering. I don't know the best ratio of the top of my head, if you research it youll find out.

I did my first 2 grows from start to finish with 5000k cfls. You can use any shade of light to grow with. Of course the better light and the closer you come to mimicking the sun the better.

I used both spectrums throughout the whole growth phase (veg and bloom) with satisfying results. The blue light helps to keep the internodal spaces more compact and also emits UV radiation which promotes trich production (hence I kept it in flowering stage as well). The red light promotes greater bud production, a bit more yield than a blue spectrum alone, but a combination combines the advantages of both. Yeah and bulbs in the blue spectrum tend to draw more electricity than their red spectrum peers although the plants obtain the same amount of energy from them (so using only red spectrum might be more economical, combining both will give generally a better bud).

Happy growing!

https://www.rollitup.org/general-marijuana-growing/9582-marijuana-light-spectrum.html

check out this thread