Odin*
Well-Known Member
@Dr. Who
Please clarify, "In over 40 years of growing...", cannabis?
You cherry picked a "buzz word" (biomass). Yes, "biomass" is used in the article, but it states that this information will be applicable amongst varying plants to generate "crops that grow faster, produce greater yields of food or generate more biomass per acre". So, yes, absolutely, manipulating the light cycle will accelerate flowering as well as increase flower production. In my experience, matured plants with a healthy root system that are subjected to 24hrs of darkness pre-12/12 will not only produce more resin, but flower material as well (larger buds).
An acceleration in the onset of flowering will result in shortened flowering time, that's a given. Apply it anywhere. All else being equal, a quicker start results in a quicker finish.
I don't need to explain the benefit of 24hrs of darkness, the research presented does that. I will say that anything longer (36, 48, 72, 96) appears to "stress" the plant, slowing onset. I suspect this is due to nutrient "exhaustion" at each bud site (exaggerated yellowing) and the plant in general.
In my experience, the difference is ~a week to 10-11 days. Purely anecdotal, but these results are (in general) amongst clones from the same mother, in the same room, introduced to bloom periodically, multiples introduced at each interval. Also illustrated varied terpene development and yield (24hrs dark being optimal). I've never counted trich's. Visual, the "nose", yield, and the smoke have been my points of reference. Pepsi Challenge amongst friends and family also.
You say "unlike"- Yes, I did, but I started that side note with "nb" (i.e.; "Nota Bene"). That highlights notable points and includes the information that follows. I did not include all of the information, "nb" highlighted an area of interest, reading that particular section would have "filled in the blanks". Anyhow, this is what I was referring to within that article;
"The situation in LDPs is, however, different. Generally they are less responsive to night break treatment (Thomas and Vince-Prue, 1997). In contrast to SDPs, longer night interruptions are needed, and the flowering response is often semi-quantitative in nature. Furthermore, in contrast to SDPs, most LDPs require far-red light at the end of the light period to interpret the light period as a long day (Thomas, 1998; Thomas and Vince-Prue, 1997). If instead far-red light is followed by red light in the second part of the day, promotion of flowering is poor or absent (Fig. 3). In SDPs the light quality given at different parts of the light period has little effect on flowering. These differences in responses to night or day are not perfectly correlated with SDPs or LDPs, and some SDPs also show a weak response to light quality during the day. For this reason, plants can be classified as either dark dominant or light dominant. SDPs are predominantly dark dominant, while LDPs are predominantly light dominant."
So, exposure to Far-Red and (deep) Red light (or any other color, for that matter) have little effect on flowering in Short Day/Long Night plants, such as cannabis.
Regardless, the information regarding Pfr and Pr (Far-Red and Red receptors), Far-Red Light and Red Light, has been misinterpreted. You are not going to get an extra 2 hours of "Lights On" by exposing the plant to Far-Red. You can, however, assist the onset of Flower by exposing the plant to Far-Red during your first "night" of transition. Far-Red exposure converts Pfr to Pr, low Pfr levels and high Pr levels trigger bloom. Once in bloom, as the article states, qualities of light make little difference (darkness converts Pfr to Pr, so 12/12 sustains low Pr). In other words, trying to get a plant to bloom that is already in bloom won't make it bloom "more".
As this change from Pfr to Pr in darkness is gradual and not immediate, the 24hr initial dark period will convert a greater amount of Pfr to Pr than 12 hours of dark will. Therefore, not only a hastened response due to inhibited ELF3, but a more potent response due to lower Pfr/higher Pr.
Perhaps "counting" was a waste of time. You can't count the qualitative increase in trichome production as you can quantify it. Terpene development, this is what I was referring to. 4-5 days in, when tiny flowers are present, the terpenes developed in that time give off a "finished" scent (when the plants are brushed against). This level of terpene development (in the strains tested) does not occur within 4-5 days of 18/6 to 12/12. With 24 hours of dark, it does.I still disagree with you on the issue! No diversion as "trichome" production is often the call of those who champion longer dark periods for growth increase! In over 40 years of growing. I have tried this idea, several times! I have yet to count any real % increase in trich's.
Please clarify, "In over 40 years of growing...", cannabis?
The plant is a Mustard plant. In college, it was the go-to plant for experiments (not so important). Your point is correct but,,,for the yield part, as WE grow FOR concerning yields to plant grown. --- What I'm saying is that the increase in the mustard plant yield is realized in total Biomass increase. NOT in flowering point increase (this is what WE would need to increase our yield) I'm saying the increase is in the increased stretch. I've seen this IN school, in an experiment close to whats going on here. Sadly, in the actual industry they quote as it helping (farming). How can we apply this extra darkness in the field?
With ALL honesty. I would use this if I could! It would increase alfalfa yields quite nicely!
You cherry picked a "buzz word" (biomass). Yes, "biomass" is used in the article, but it states that this information will be applicable amongst varying plants to generate "crops that grow faster, produce greater yields of food or generate more biomass per acre". So, yes, absolutely, manipulating the light cycle will accelerate flowering as well as increase flower production. In my experience, matured plants with a healthy root system that are subjected to 24hrs of darkness pre-12/12 will not only produce more resin, but flower material as well (larger buds).
Plant descriptive terms - YUP. Ok, your correct on the second part too! BUT, it's not an acceleration IN flowering. It's an acceleration TO flowering, (faster flowering onset)......In every experiment I have ever done to attempted to decrease the flowering time by increasing the darkness at the transition, it did notgive a significant return! It did so little, other then give increased node spacing - that I don't do it! I can't for the life of me remember the kids name in school who tried this in his grow. It didn't work for him either and we were taking mostly AG classes!
An acceleration in the onset of flowering will result in shortened flowering time, that's a given. Apply it anywhere. All else being equal, a quicker start results in a quicker finish.
I don't need to explain the benefit of 24hrs of darkness, the research presented does that. I will say that anything longer (36, 48, 72, 96) appears to "stress" the plant, slowing onset. I suspect this is due to nutrient "exhaustion" at each bud site (exaggerated yellowing) and the plant in general.
I gotta ask then (Trust me, I have not the lack of understanding you speak of [not offended either] and I'm not attacking you either!)
Tell me please. How many days does this 24hr darkness remove from normal bloom times?
Did you do a side by side? Same mother for the clones? Run more then a cpl of plants and a side control? Did you actually do any trich counts per sq. mm? (If it looked possible in mine, I did cm counts too!) These turned turned out to be a non-affect percentage wise!
In my experience, the difference is ~a week to 10-11 days. Purely anecdotal, but these results are (in general) amongst clones from the same mother, in the same room, introduced to bloom periodically, multiples introduced at each interval. Also illustrated varied terpene development and yield (24hrs dark being optimal). I've never counted trich's. Visual, the "nose", yield, and the smoke have been my points of reference. Pepsi Challenge amongst friends and family also.
You say "unlike"
Cannabis does react directly to the pfr bands of light (DEEP reds)! All C3 plants do! The bands that are involved are like the 724 to 736 nm range, with the greatest response/effect between 727 to 733nm. This is considered the spectral banding that puts the plant to "sleep". In nature you get this right before sunset into darkness after sunset. This is a period of around 2 hrs of weak exposure. If you give indoor MM a dose of this with 10w 730nm diode LEDs (covers a 10x10 area effectively). The plant is completely at rest in less then 15 min!
The idea of this being, that you can increase lights on times in bloom by those 2 hrs, and increase the yield. I did this several times in several area's. I ran 3 light area's and 3 control area's. IT WORKED! But, found that in my case. The cost to return ratio as being a not viable situation.
You say "unlike"- Yes, I did, but I started that side note with "nb" (i.e.; "Nota Bene"). That highlights notable points and includes the information that follows. I did not include all of the information, "nb" highlighted an area of interest, reading that particular section would have "filled in the blanks". Anyhow, this is what I was referring to within that article;
"The situation in LDPs is, however, different. Generally they are less responsive to night break treatment (Thomas and Vince-Prue, 1997). In contrast to SDPs, longer night interruptions are needed, and the flowering response is often semi-quantitative in nature. Furthermore, in contrast to SDPs, most LDPs require far-red light at the end of the light period to interpret the light period as a long day (Thomas, 1998; Thomas and Vince-Prue, 1997). If instead far-red light is followed by red light in the second part of the day, promotion of flowering is poor or absent (Fig. 3). In SDPs the light quality given at different parts of the light period has little effect on flowering. These differences in responses to night or day are not perfectly correlated with SDPs or LDPs, and some SDPs also show a weak response to light quality during the day. For this reason, plants can be classified as either dark dominant or light dominant. SDPs are predominantly dark dominant, while LDPs are predominantly light dominant."
So, exposure to Far-Red and (deep) Red light (or any other color, for that matter) have little effect on flowering in Short Day/Long Night plants, such as cannabis.
Regardless, the information regarding Pfr and Pr (Far-Red and Red receptors), Far-Red Light and Red Light, has been misinterpreted. You are not going to get an extra 2 hours of "Lights On" by exposing the plant to Far-Red. You can, however, assist the onset of Flower by exposing the plant to Far-Red during your first "night" of transition. Far-Red exposure converts Pfr to Pr, low Pfr levels and high Pr levels trigger bloom. Once in bloom, as the article states, qualities of light make little difference (darkness converts Pfr to Pr, so 12/12 sustains low Pr). In other words, trying to get a plant to bloom that is already in bloom won't make it bloom "more".
As this change from Pfr to Pr in darkness is gradual and not immediate, the 24hr initial dark period will convert a greater amount of Pfr to Pr than 12 hours of dark will. Therefore, not only a hastened response due to inhibited ELF3, but a more potent response due to lower Pfr/higher Pr.