# Question about light cycle?



## bigdrov1x (Jan 31, 2011)

I found a few hermies in my bloom room.  My lights are on during the night 6pm-6am.  I chopped these plants down.  I have a few others that are in the bloom room, but havent shown any pistils yet, and I have a few that have all white pistils.  I turned the fans off, and sprayed the room and mopped the floor.  My question is if I changed my lights to being on during the day time by giving them an extra 12 hrs of dark.  Would that stress them out some more.  I know that my room is light tight at 6 am, but I cannot tell if it is at noon because I cannot get in there.  I know for a fact that at midnight or 3 am, the room would be extra dark with no daylight getting in through a crack or something I have not noticed. any advice would be appreciated. Thank You


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## umbra (Jan 31, 2011)

The extra 12 hrs dark should not stress the plant. To the plant, its like a cloudy day.


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## dman1234 (Jan 31, 2011)

Ive done it a few times, the extra 12 of dark wont hurt at all.


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## The Hemp Goddess (Jan 31, 2011)

bigdrov1x said:
			
		

> I found a few hermies in my bloom room.  My lights are on during the night 6pm-6am.  I chopped these plants down.  I have a few others that are in the bloom room, but havent shown any pistils yet, and I have a few that have all white pistils.  I turned the fans off, and sprayed the room and mopped the floor.  My question is if I changed my lights to being on during the day time by giving them an extra 12 hrs of dark.  Would that stress them out some more.  I know that my room is light tight at 6 am, but I cannot tell if it is at noon because I cannot get in there.  I know for a fact that at midnight or 3 am, the room would be extra dark with no daylight getting in through a crack or something I have not noticed. any advice would be appreciated. Thank You



You can always just turn out the lights for a few moments and go into your grow space to see if light is getting in...  

Changing the dark hours to night is only going to help if there is no light that is turned on in a room that is adjacent to the grow space.  While it will not do your plant any harm to change the light cycle, I would really advise making sure that your grow space is 100% dark during the dark time.


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## bigdrov1x (Jan 31, 2011)

turning off the lights for a few seconds will not hurt the plants or stress them?


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## Locked (Jan 31, 2011)

You worry about light leaks in the dark period not about dark in the light period...like Umbra said it is like a dark cloudy day...turning the lights off for a bit while you attend to something won't hurt them in my opinion. It is light interrupting the dark period that is stressful and can contribute to hermaphrodites.


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## bigdrov1x (Jan 31, 2011)

thanks guys for the help!!!


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## biggerbuds (Feb 26, 2011)

bigdrov1x said:
			
		

> turning off the lights for a few seconds will not hurt the plants or stress them?


 
No it will not hurt them at all,its only the same thing as what happens when there is an eclipse in nature.


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## StoneyBud (Feb 26, 2011)

As an interesting side remark, a few years ago, in one of the many grow books, I found a mention about a study where strobing lights were tested on marijuana growth.

It said that during the normal lights on period, the lights could strobe at as much as a minute off and a minute on without the plant "noticing" the difference. I don't remember the exact times mentioned, but I'm pretty sure it was about a minute or so.

I've always thought that was interesting and if I had the space, I would like to try that one day to see in a side-by-side grow if it holds water.

Has anyone else read about that and remembers the timings?


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## pcduck (Feb 26, 2011)

Stoney I remember reading about that years ago, but do not remember the times. I keep thinking that it was a rapid on and off sequence of floro's that they were using. Like 10 seconds on then 10 off, but not sure.


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## StoneyBud (Feb 26, 2011)

pcduck said:
			
		

> Stoney I remember reading about that years ago, but do not remember the times. I keep thinking that it was a rapid on and off sequence of floro's that they were using. Like 10 seconds on then 10 off, but not sure.


 
Well that's just Ducky! hahaahaha

Thanks for the verification! I think it was Ed Rosenthal's reporting. Heck, I've read so many of the grow books that they all start blending together after awhile.

I hardly remember the article, it was so long ago, and I don't remember the type of light. Maybe someone with that book will come into the thread and remind me.


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## Melvan (Feb 26, 2011)

If there's no difference between "strobing" light and light on steady, what would be the purpose of it? I know it would be a "fun" study, but why bother if it isn't something that improves the plant growth or yield?


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## Locked (Feb 26, 2011)

Melvan2 said:
			
		

> If there's no difference between "strobing" light and light on steady, what would be the purpose of it? I know it would be a "fun" study, but why bother if it isn't something that improves the plant growth or yield?



I wonder if strobing the bulb wld ultimately lead to a shorter life?


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## Wetdog (Feb 26, 2011)

Melvan2 said:
			
		

> If there's no difference between "strobing" light and light on steady, what would be the purpose of it? I know it would be a "fun" study, but why bother if it isn't something that improves the plant growth or yield?



Hee Hee, yeah.

I 'sorta' remember what they are talking about (the test), but I saw so many strobe lights in the '60's and 70's, I didn't need to see anymore. LOL

Wet


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## pcduck (Feb 26, 2011)

Melvan2 said:
			
		

> If there's no difference between "strobing" light and light on steady, what would be the purpose of it? I know it would be a "fun" study, but why bother if it isn't something that improves the plant growth or yield?



I think they were concerned with cost effectiveness of the study. If they could get the same harvest with half the cost.(the light being on only half the time as a steady light.)


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## Hick (Feb 27, 2011)

pcduck said:
			
		

> I think they were concerned with cost effectiveness of the study. If they could get the same harvest with half the cost.(the light being on only half the time as a steady light.)


 ..."to ME",... that doesn't make any sense at all. I would think "restarting" a lamp over and over, would not only be harmfull to the 'bulb life', but would also require more power useage.


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## pcduck (Feb 27, 2011)

Hick said:
			
		

> .."to ME",... that doesn't make any sense at all. I would think "restarting" a lamp over and over, would not only be harmfull to the 'bulb life', but would also require more power useage.



If my recollection is correct that is the same conclusion that they arrived at.


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## StoneyBud (Feb 27, 2011)

Hick said:
			
		

> ..."to ME",... that doesn't make any sense at all. I would think "restarting" a lamp over and over, would not only be harmfull to the 'bulb life', but would also require more power useage.


 
I guess that would depend on what type of light was used as the strobe. In just a short search, I found this:

---
&#8220;Some botanists have speculated that the pigments which are us-
ed in photosynthesis respond to energy peaks in the light wave.
These scientists believe that much of the light is wasted by the plant
because it isn't "peak". They speculate that much energy could be
saved by supplying the plant only with light "peaks". One way to
do this is by using a strobe unit in place of conventional lighting.
The strobe flashes a high intensity of light, but it is on for only frac-
tions of a second. The result is that the plants receive many light
peaks in between periods of darkness. There has been little research
on this theory, but one grower claimed to get satisfactory results.
One way to use a strobe without too much risk might be to use
it to supplement more conventional lighting. If a higher growth rate
is noticed, the strobes could be tried alone. Should this system
work, electrical costs could be lowered by as much as 75%.&#8221;
---

--- 
The Effect Of Strobe Light on the Growth of Millet Plants

Abstract. Ten millet seeds (Panicum miliaceum) were planted in clear Dixie cups. One was placed in a window and the other in a dark closet with no light other than a strobe light. The strobe light was placed on its lowest setting. The strobe light was the only variable in this experiment. Plants were thinned to three plants per cup after one week. The plants&#8217; growth was measured every other day starting from day seven to day twenty-nine after planting. The plants put under the strobe light grew taller than the plants in the window. The final average growth of the control plants was 99.33mm + 2.08mm. The final average growth of the control plants was 123.80mm + 2.31mm.
Introduction. Some botanists have suggested that the pigments which are used in photosynthesis respond to energy peaks...
---
Of course, using a strobe on MJ plants may well be way different than using a strobe on millet plants. We really don't want "tall" as much as "bushy", and that might be a real concern.

I just thought it was an interesting theory. I'm certainly not suggesting that anyone toss their HPS, MH, CMH, FLO's or even their LEDs and replacing them with strobes.  :doh:


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