[Scrogerman]

You the man Spurr, Tagged! another quality thread k+

[spurr]

Here is a great read in the newest edition of Plant Physiology online companion (5th ed):

"Know Thy Neighbor through Phytochrome"
C. L. Ballaré, A. Scopel, J. J. Casal and R. A. Sánchez, IFEVA,
Facultad de Agronomía, Universidad de Buenos Aires and CONICET.
https://5e.plantphys.net/article.php?ch=e&id=236

[Dave Coulier]

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[spurr]

Originally Posted by VerdantGreen

p.s. also while we are talking far red i heard somewhere that far-red increases resin production - any comments on that ??

So far, I have not found much, but I did find one neat study, uploaded in this post

"EFFECT OF LIGHT QUALITY ON CANNABINOID CONTENT OF CANNABIS SATIVA L. (CANNABACEAE)"
PAUL G. MAHLBERG AND JOHN K. HEMPHILL
BOT. GAZ. 144(1):43-48. 1983

Plants of a drug strain of Cannabis sativa L.-grown 33 days under daylight, shaded daylight conditions, filtered green, blue, and red light, and darkness-were analyzed by gas-liquid chromatography for their cannabinoid content.

The highest content of cannabinoids, predominantly 9-tetrahydrocannabinol (9-THC) in this strain, occurred in the youngest leaves of daylight-grown plants. Leaves at successively lower nodes of this control condition and all treated plants subsequently grown in daylight contained progressively lower levels of cannabinoids.

Leaves from plants grown under filtered green light and darkness contained significantly lower levels of 9-THC than those from plants grown in daylight. However, the 9-THC content of leaves from plants grown under shaded daylight and filtered red and blue light did not differ significantly from the 9-THC content in daylight controls, indicating that these conditions did not alter the synthetic rate of this cannabinoid.

The cannabichromene (CBC) content of plants grown under filtered red and green light and darkness differed from the CBC content in plants grown in daylight, indicating that theformation of this cannabinoid was independent of 9-THC. Leaves from plants grown under filtered red and green light and darkness recovered the capacity to synthesize typical levels of 9-THC and CBC when placed under daylight conditions. Plants from all light and dark treatments, when subsequently placed under daylight conditions for 66 days, attained levels of cannabinoid synthesis comparable to the daylight controls

[Dave Coulier]

Originally Posted by imadoofus

it has been speculated on other forums ambient temperature fluctuations during the day/night cycles contributes significantly to stretching during the onset of flowering.

several mods on serious seeds forums relate similar validations regarding this.

researching different light studies for my upcoming mh/hps comparison has revealed a reoccuring theme on how regardless of using a mh/hps for flowering, the stretch was the same given for each strain used.

I mean to respond to this sooner, but forgot.

Do you have sources for your statement? I ask because I have seen beautiful short compact plants under 6500k T5's become very leggy when they started to shade each other. Excessive temperatures will also counteract the effects blue light has on internodal elongation.

If plants were spaced out, and temperatures were ideal, I would expect there would a noticeable difference between HPS and MH effects on controlling the stretch.

[imadoofus]

sources, you ask for? of course not! what kinda troll would i be if i did?

lol...

all completely heresay, but nonetheless, reoccuring heresay; perhaps, it has merit ; )

[Dave Coulier]

Originally Posted by imadoofus

sources, you ask for? of course not! what kinda troll would i be if i did?

lol...

all completely heresay, but nonetheless, reoccuring heresay; perhaps, it has merit ; )

There is no need to act that way. I was offering you reasons why what you have heard may not be 100% true. Plenty of the grows you'll see on this forum have plants that are badly over-crowded, and that will trigger SAS(Shade Avoidance Syndrome), and no matter how much blue light you supply your plants with, I guarantee that they will stretch.

Read this if you want to educate yourself and stop relying on hearsay. Its a great read posted by Verdant Green.

[VerdantGreen]

Originally Posted by spurr

So far, I have not found much, but I did find one neat study, uploaded in this post

"EFFECT OF LIGHT QUALITY ON CANNABINOID CONTENT OF CANNABIS SATIVA L. (CANNABACEAE)"
PAUL G. MAHLBERG AND JOHN K. HEMPHILL
BOT. GAZ. 144(1):43-48. 1983

cool, thanks, the paper seems to find that 'regular' spectrum doesnt unduly effect THC content. i dont think the phlexiglass would have blocked far red light.

[VerdantGreen]

Originally Posted by spurr

Here is a great read in the newest edition of Plant Physiology online companion (5th ed):

"Know Thy Neighbor through Phytochrome"
C. L. Ballaré, A. Scopel, J. J. Casal and R. A. Sánchez, IFEVA,
Facultad de Agronomía, Universidad de Buenos Aires and CONICET.
https://5e.plantphys.net/article.php?ch=e&id=236

this is also a nice short but informative read. i have a few Deep Chunk plants atm and as soon as they started running out of space the increase in stretch is huge!

[IMO]

not really sure about the rules on this forum but if anyone is bugged by this by all means remove it... as many other members, i am on many forums. while doing my own research into lighting i came across this grow i found this grower to be quite knowledgeable and worth looking into what he is doing. I think a lot of the leg work you guys are talking about has been done by him in some capacity. i encourage you to take a look.

here's the journal to match that build