"I have heard that 660nm Red extends the flowering cycle instead of reducing it. I have heard that it is better to use a combination of 640nm and 630nm instead of 660nm."

Aloha Shintooo

Hearsay, being what it is, can be misleading.
I don't claim to be an expert, but my experimentation indicates that 660nm.
deep red is the most efficient wavelength for cannabis photosynthesis.
(Actually is 657nm. according to the books.)
If, it does indeed extend the flower cycle, that's a good thing for personal grows.
Allows one to really pack on the resin.
So, might take longer, but medically, it's a net win in Milligrams/Gram of active ingredient.

2 cents, please.
Weeze
Weezard Reviewed by Weezard on . UVb an experiment Quick background: I have been using UVb supplemental lighting for many years now and have always thought it added to the finished product in a couple of ways. I had never promoted it's use on these boards because I felt it was dangerous and had real potential to harm people. That changed a few months back on the other UVb thread, and I came out of the closet in strong support of it's use. Well some here who's opinion I respect (like Weezard) held the opposite view and those discussions led me Rating: 5