these are my own words fyi, you have my permission to repost but with credit via link so the whole thread is cited etc (this has been a communal project, lead by respected members of the forum)
Hey all this was originally just a pm I sent to undercover but he said it was helpful and I guess I can just copy it to here too, was trying to relax a bit before I posted more since I let someone I wont even mention get to me a touch.
So here ya go,
Blue light:
Causes phototropism (plants grow towards it if there is a clear “area with blue” and “area without” they will favor the former. Provide enough and you have created an environment which may signal to the plant (via saturation, or oversaturation---yes it is possible to deliver too much light) that it should not/will not grow anymore. Because the ratio of “good quality light” (PAR) to infrared is known to bring about specific genetic expression changes (morphisms) such as generative expression, which we commonly call “flowering” (yes photoperiod does this too). I submit that these ratios, when changed, cause stress to the plants and the generative expression is a survival response to the stress.
**edit** Also I've gone over lower canopy light before, and rehash it shortly but while I'm on generative expression and stress, think about what lower canopy light signals:
My flowers also don't get the wind. And all the good lookin females are up nude-sunbathing (RE: trichs as sunscreen) in the good quality light....
If this is a male, this could be the difference between survival or not. Anyone ever seen a male stretch? No doubt. Look at corn plants... holy cow! The Takeway from the edit---> ever heard of hermies? wonder if green light might trigger hermie response (+/- other stress factors withstanding)? don't we all...
So two concepts for bulb selection, placement, and light management (reflection)
1) Photoperiod is what you are going to use to initiate generative expression, you do not need to change your bulb colors, like that pinky? Get it in there from the get go. There are links showing the light quality will effect gene expression of the plant later on. Drastic (not that 1-3 out of an 8 bulb setup is that drastic) changes should be assumed to disrupt the circadian rhythm of the plant and will be an additional source of stress.
2) Sun irradiance graph is essential (Wikipedia on sunlight) the upper line is higher atmosphere radiation, there is another for sea level. Most likely mountain strains expect something closer to the PAR ratios seen in the upper atmosphere light, moreso at least than the balance seen in sea level. I take this to mean that one may push the low nm light a bit more (as we all know the prof and others have cited the 1986-7 studies showing increase in cannabinoids resulting from UVb exposure) There are also solid links between plants with anthocyanin (red pigment) and increased flux capacity tolerance for blue light spectrum---they can handle more before becoming overloaded/oversaturated. Again back to the graph, certain compounds/elements absorb certain ranges, something you see in the difference between the sea level and the upper atmosphere light spectrum ratios (favoring the blue more in the upper atmosphere, more flat in the sea level). 2 things from this—sea level plants in addition to canopy filtering (only yellow/green/infrared gets through) have atmospheric filtering. So results seen with mountain strains are not consistent with others, and hybrids are a dice-roll depending on which sets of predetermined favored genes you draw (and are thusly expressed at the expected junctures) How do you take this info and maximize your efficiency in an indoor growing environment? You need to keep your reflectors close to the center of irradiation (tents work great for this), keep the lights close too---a PAR meter or even a photometer measuring lumens should help as you are trying to determine the general field of emission from the light and maximize your placement choice results, the photon emission “degradation” at measured distances could help you figure this out. After reflectors and light distance is in check, you will want to train your plant to maximize the different growing environment, luckily mountain strains are already genetically prepared for this—short veg periods, early quick flower, etc. Pick the line on the sun graph you want to emulate, combine single or select banded bulbs that get an average “unit” (light fixture) emission of the banding range you want and you are ALL SET FOR A PAR GRO BROTHA
Please hit me back with any questions,
MPP
edit:
this may help, if you can get to it:
http://www.springerlink.com/content/a3527u6018823x43/