Quick question , has anyone turned lights off near harvest date??

[Castro4747]

I heard this strategy before but I thought it's too risky to carry out, all that effort gone to waste in a night! But I have seen some videos of people doing it before harvest and the yield turned more denser and more in quantity, supposingly it's some sort of plant defence mechanism?

Thanks for any input and advice available

 

[BSD0621]

It is said a cannabis plant left in 2-3 days total darkness the resin production will increase (I call bullshit on this. Trichomes act as a pesticide capturing little bugs and as a magnifier for light. How one get's increased trichome production in total darkness is very contradicting) as far as denseness, cannabis plants do that before the final days where it'll reach max potency (almost all trichomes will be cloudy) then the trichome degrades into CBN (amber trichomes) Seem's like this "theory" has been going around since I was young and still no proof it even works... just word of mouth. If anything, stop watering 3-4 days before you are going to harvest to dry out the stem more (cut down on drying time) and the plant will naturally pop out more trichomes as a defense mechanism (I have seen this with my own eyes and you will too if you try it)

 

[tip top toker]

There has been one study posted that saw a 30 percent increase in THC production or something, but the source in not verifiable. Simply put it seems like one of many growing ideas that might just cause a growth change, but a change that is not discernable to the user, nothing but a lower number on a piece of paper.

 

[Castro4747]

I hear what you gents mean, I will try and find a video I found a while back on this theory, seemed like the guy got a lot out of it, it's them guys from Amsterdam calling themselves the strain hunters

 

[tip top toker]

I hear what you gents mean, I will try and find a video I found a while back on this theory, seemed like the guy got a lot out of it, it's them guys from Amsterdam calling themselves the strain hunters

If they are the strainhnters as in greenhouse seeds, then I would take what they say with caution. They are advertisers before they are breeders.

 

[mrCRC420]

It makes sense to me, maybe for 12-48 hours. It's giving the plant an extended period of growth. You could do it at any stage of flower; perhaps folks do it near the chop because extended dark may stress the plant. If you're going to do it, I'd suggest giving the plants as much light as you possibly can without burning them during the last 12 hours of light; this way they've stored up an unusual amount of energy to be expended during the dark cycle. I've used this technique before, years ago; I honestly have no record of the results. However, what I do now, is flower under MH light during the last 2-3 weeks in order to force the plant to produce more resin (as a "sunblock" against the UV rays from the MH HID light). I also flower under MH for the first 2-3 weeks to ease the transition from Veg to Flower. ::breath:: GL.

 

[chuck estevez]

read this thread, especially the part on making it rain. https://www.rollitup.org/general-marijuana-growing/409622-truth-about-flushing.html

 

[Castro4747]

This is the video http://m.youtube.com/watch?ipadtype=3&sts=15988&utcoffset=60&v=1dcWWF1Gt5o&has_verified=1&client=mv-google&layout=tablet
If the URL don't work type in YouTube.grow hd tv its the 15 min long one, it's worth watching though
let me know what you think of there methods.
p.s I fucking hate the way these guys talk.

 

[Castro4747]

Okay so it didn't mention nothing about which I thought it did, but there was another interesting technique, starving the plant, what do y'all think, personally I think it's a it bullshit but who knows, they supposingly did manage to get just over 1gpw

 

[Castro4747]

It makes sense to me, maybe for 12-48 hours. It's giving the plant an extended period of growth. You could do it at any stage of flower; perhaps folks do it near the chop because extended dark may stress the plant. If you're going to do it, I'd suggest giving the plants as much light as you possibly can without burning them during the last 12 hours of light; this way they've stored up an unusual amount of energy to be expended during the dark cycle. I've used this technique before, years ago; I honestly have no record of the results. However, what I do now, is flower under MH light during the last 2-3 weeks in order to force the plant to produce more resin (as a "sunblock" against the UV rays from the MH HID light). I also flower under MH for the first 2-3 weeks to ease the transition from Veg to Flower. ::breath:: GL.

Yes i think you are right, it's to give the plant stress so it starts it's own defence against cold etc, what do think of the starvation method?..

 

[BSD0621]

It makes sense to me, maybe for 12-48 hours. It's giving the plant an extended period of growth. You could do it at any stage of flower; perhaps folks do it near the chop because extended dark may stress the plant. If you're going to do it, I'd suggest giving the plants as much light as you possibly can without burning them during the last 12 hours of light; this way they've stored up an unusual amount of energy to be expended during the dark cycle. I've used this technique before, years ago; I honestly have no record of the results. However, what I do now, is flower under MH light during the last 2-3 weeks in order to force the plant to produce more resin (as a "sunblock" against the UV rays from the MH HID light). I also flower under MH for the first 2-3 weeks to ease the transition from Veg to Flower. ::breath:: GL.

now THAT makes sense. MH lights put out more UV-B rays which would increase trichome production as they act as a UV-B blocker for the leaf's.

 

[BSD0621]

And the starvation period I will say is true. I have let my plants dry out during flowering and have noticed plenty of new clear tichomes popping up when doing so.

 

[chuck estevez]

now THAT makes sense. MH lights put out more UV-B rays which would increase trichome production as they act as a UV-B blocker for the leaf's.

MH does not put off barely any UV-B


UVB - 280 to 315 nm

Here is the range of a 600 MH eye hortilux


Notice the Uv-b range is not even on the chart.

 

[BSD0621]

MH does not put off barely any UV-B


UVB - 280 to 315 nm

Here is the range of a 600 MH eye hortilux


Notice the Uv-b range is not even on the chart.

Wrong! http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/mwmhl/work.asp
Metal halide light DO emit UV rays.

"How do metal halide lamps work?

Metal halide (MH) lamps consist of an arc tube (also called a discharge tube or "burner") within an outer envelope, or bulb. The arc tube may be made of either quartz or ceramic and contains a starting gas (usually argon), mercury, and MH salts. Traditional quartz MH arc tubes are similar in shape to mercury vapor (MV) arc tubes, but they operate at higher temperatures and pressures.
MH lamps start when their ballast supplies a high starting voltage higher than those normally supplied to the lamp electrodes through a gas mixture in the arc tube. The gas in the MH arc tube must be ionized before current can flow and start the lamp. In addition to supplying the correct starting voltage, the ballast also regulates the lamp starting current and lamp operating current. (See "What types of ballasts are available to use with metal halide lamps?")
As pressure and temperature increase, the materials within the arc tube vaporize and emit light and ultraviolet (UV) radiation. A bulb (also called "outer jacket" or "outer envelope"), usually made of borosilicate glass, provides a stable thermal environment for the arc tube, contains an inert atmosphere that keeps the components of the arc tube from oxidizing at high temperatures, and reduces the amount of UV radiation that the lamp emits. Some MH lamps have a coated finish on the inside of the bulb that diffuses the light. Often a phosphor coat is used to both diffuse the light and change the lamp's color properties."

If you SEARCH you will find numerous results, all the same. Even Ed Rosenthal states MH emits UV-B rays... Please don't talk about something you don't know about. Even HPS emit UV-B rays but MH emit more.

 

[BSD0621]

Also, reading material http://onlinelibrary.wiley.com/doi/10.1111/j.1751-1097.1987.tb04757.x/abstract

 

[BSD0621]

examples of HIGH THC producing areas and there UV index


Country (City) . J F M A M J J A S O N D

Brazil (Rio de Janeiro) 23°S 12 11 9 7 5 5 5 7 9 10 12 12

Kenya (Nairobi) 1°S 12 13 13 12 11 10 11 11 12 12 12 11

Vietnam (Hanoi) 21°N 6 8 10 11 11 11 12 12 10 8 6 6


Cuba (Havana) 23°N 6 8 9 10 10 11 12 11 10 8 6 5

Panama (Panama) 9°N 9 11 12 12 11 11 12 12 12 11 9 9

& for comparison
Australia (Sydney) 34°S 9 9 7 5 3 2 3 4 6 7 9 10
Australia (Darwin) 13°S 12 13 12 10 8 8 8 10 11 13 12 12

USA (Los Angeles) 34°N 3 4 6 8 9 10 10 9 7 5 3 2
USA (New York) 41°N 2 3 4 6 7 8 9 8 6 3 2 1

 

[BSD0621]

And the explanation for your chart is the human eye cant see below 400NM so I figure that is why they didn't include it. also, trichomes will increase in production with higher UV-B ray as one of it's purposes is to PROTECT the plant by ABSORBING the UV-B rays VIA the trichomes. So, more UV-B more trichomes to an extent. WARNING! UV-B rays will burn your eyes!

 

[chuck estevez]

Wrong! http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/mwmhl/work.asp
Metal halide light DO emit UV rays.

"How do metal halide lamps work?

Metal halide (MH) lamps consist of an arc tube (also called a discharge tube or "burner") within an outer envelope, or bulb. The arc tube may be made of either quartz or ceramic and contains a starting gas (usually argon), mercury, and MH salts. Traditional quartz MH arc tubes are similar in shape to mercury vapor (MV) arc tubes, but they operate at higher temperatures and pressures.
MH lamps start when their ballast supplies a high starting voltage higher than those normally supplied to the lamp electrodes through a gas mixture in the arc tube. The gas in the MH arc tube must be ionized before current can flow and start the lamp. In addition to supplying the correct starting voltage, the ballast also regulates the lamp starting current and lamp operating current. (See "What types of ballasts are available to use with metal halide lamps?")
As pressure and temperature increase, the materials within the arc tube vaporize and emit light and ultraviolet (UV) radiation. A bulb (also called "outer jacket" or "outer envelope"), usually made of borosilicate glass, provides a stable thermal environment for the arc tube, contains an inert atmosphere that keeps the components of the arc tube from oxidizing at high temperatures, and reduces the amount of UV radiation that the lamp emits. Some MH lamps have a coated finish on the inside of the bulb that diffuses the light. Often a phosphor coat is used to both diffuse the light and change the lamp's color properties."

If you SEARCH you will find numerous results, all the same. Even Ed Rosenthal states MH emits UV-B rays... Please don't talk about something you don't know about. Even HPS emit UV-B rays but MH emit more.

We can agree to disagree, to get ANY kind of usable uv-b, you need a tanning bulb or reptile bulb.

 

[FilthyFletch]

I always do 48 hours darkness before harvest. I also cut off food and water. The purpose of this is the plant thinks it is going to die so it uses last stored food and water and helps break down starches which in turn become basic carbohydrates which then are used in producing thc which the plant creates in an effert to survive. The lack of water means the plant uses stored water which cuts down the drying time. I persoanlly had tried few expirements and liked the outcome and have done it since the last 12 or so years.

 

[tip top toker]

Any reasoning you have for doing this, or anyone else's reasoning, such as they build up THC overnight to be broken down at day, is purely theoretical hypothesis. There has been one vague unconfirmable study given, other than that, nothing but, truthfully, uneducated opinion. My own test, showed to me that there was no difference. Whether there is a statistical difference, I found no discernable difference from a strain I knew like the back of my hand. You might as well try sticking nails through your stems.

OP just focus on getting the hang if the aerioonic system, then look at hiwnto increase yield. And I guarantee, there will be a plethora of methods to genuinely increase your yield before you have to consider a day or two in complete darkness.