I'd like to take the time to direct you all to this link... http://www.plantphysiol.org/cgi/content/abstract/137/1/199 Here's a snippet of what you can expect to read when you get there... This is the only test of its kind, and only done on one species of plant.
I figure mimicing nature is probably best. Plants have had a long time to evolve so I'm sure they have adapted. Wish I could articulate better but I'm stoned and can't get what I'm thinking out.
Ever wondered why you feel better in the summer? It's not just the readily available heat, but also the light. UVB in particular. Even though there are still plenty of red photons and they still far outweigh the blue, there are more blue photons. So we have more good light hitting us. The same thing works for plants... cannabis would fare better if it didn't have a 'Fall' season to finish off in. Which implies that blue photons, being a richer source of light are more prized by the plant. However, there does appear to be a downside in the enhancement of the blue spectrum. If we go by the experiment in the above link, a plant with excess cryptochromes or a plant grown in an abundance of blue light will delay flowering time. But what do we take this to mean exactly? Well after clicking to read the full article on the effects on flowering time, I discovered that they took it from the seedling stage to the signs of the first flower. We all know flowering itself is genetic, right? Yet I know this to be untrue of cannabis (the maturation part). I have seen plants vegetated in a pure UV (a and B) environment and the plants showed sex in 4 weeks. To be sure, tests would need to be done on cannabis... anyone got a lab?
I can tell you that from my most recent project that a single shiva was grown under blue cfl for approximate 8 months. (No red spectrum lights were used at all, also no natural sunlight). After about the 3-4 mo period, she began to flower by herself, without any light schedule changes. The only reason she died is because the power went out for four consecutive days hence no light at all, just pure darkness . I believe that she could have survived a lot longer given more light.
From carefully watching my plants I've seen the following results comparing blue and red lighting: Red Spectrum Light = shorter, higher density, increased width, more filling out, GENERALLY HIGHER YIELD WITH A LOWER AMOUNT OF TRICHOMES (LOWER POTENCY) Blue Spectrum Light = longer/taller , lower density, more skinny and lanky than under red spec, GENERALLY LOWER YIELD BUT VISIBLY HIGHER AMOUNT TRICHOMES (HIGHER POTENCY) I believe you will get the greatest yeild if you mix and match your blue and red lights, using a very roughly equal amount during flowering, In effect - customizing how YOU want YOUR buds to grow. and yes i do know this will be like 3 years too late.
i my self have grown plants under a MH and a HPS . i would say i liked the grow with the 150 watt HPS more then 175 watt MH from what i know adding both lights is best . just from what i have done i pick the red light . under a 175 watt MH i had streching , airy buds , and a harder time all around could just be me . but i use a 1000w MH and a 1000watt HPS for what i do now .
I am growing aeroponically under 2 LEDs. I am using 1 360 adv LED with blue and red spectrum, and 1 under 180 extreme blue spectrum. I am vegging 8 with a 20/4 cycle and I have one in dirt for 12/12. The growth under the blue and red/blue spectrum has been unexplainable. I'm on a mission. I am hoping to beef up my soiled adopted daughter during flowering with the combination of lighting. The dispensary she came from was killing her with the lack of care. If you got a few bucks to toss around.... LED Grow Lights - Best New LED Grow Light
Well im glad to hear that the blue lighting only delays/slows flowering, I have a plant I moved outside and the light schedule change induced flowering. Im only about 4 weeks or so into flowering but I was wondering about how long it will take it to finish up. Its an indica dominant hybrid btw.
I have 5 plants all growing in a closet space with white walls . 3 Grow lights. 1fan. 2 1250 lumens cfl lights and one 1000 lumen Cfl blue light. Plants are loving it. Using the 12/12 schedule also