How lightproof is lightproof enough?

[MPL]

No, not touche. You were correct in your usage of the term as it relates to this discussion.

We are using connotative meanings here, as should be plainly obvious by the title of this thread. If Stainless lacks the reading comprehension to be able to understand the discussion, that's fine. He's so stuck on one particular definition of a word that he can't actually take part in the discussion. The irony is that word isn't even being used that way.

This is basic reading comprehension for any 101 level logic, comprehension or linguistics class.

Again, connotative, not denotative meaning here.



*edit*
Nevermind all that let's just leave it your opinion is appreciated but the argument is not. Stainless feels 100% lightproof is required, that's the relevant information.

Touché

 

[MPL]

Has anyone ever seen a side-by-side comparing the effects of various level of interruption of the dark cycle with light?

A full moon is ~1 lux in the tropics. We know that tropical varieties of cannabis do just fine in there. So therefore we can at least say that 100% removal of all light sources is unnecessary in some cases.

This is not to say that some strains are not significantly less tolerant of light stress.

Generally, a full moon averages about 0.25 lux. Generally, in my experience, I have never had a plant that hermied under a full moon at my latitude. Not of any strain.

100% lightproof, can, however, save a lot of stress later in a grow if one isn't familiar with the light tolerance of a particular strain.

I'm curious about this because it's an unanswered question as far as I can tell and I really hate not knowing what is really true and what is not.

 

[Avinash.miles]

Troll battle
over impenetrable

i think getting your room as light proof as possible is def worth the effort.
my2c

 

[Bobby Stainless]

Light proof equals NO light. If light is getting in... Not light proof. Really simple.

Like I said before, if you want hermies, then let light leak in.

DJ Short seems to agree with me....

Nights of total darkness

An important thing to remember about the indoor bud cycle is that the dark period must be absolute and uninterrupted. The room must be thoroughly sealed to be completely dark when the lights are off. The only way to test this is to sit in the room in the dark, either during the day or with any lights outside the room on, to check for light leaks. It is advisable to allow your eyes to adjust to the darkness before declaring the room adequately sealed.

Once the bud cycle has begun it is important to never interrupt the dark period with any light, even for a short period of time. Doing so may interrupt the long, slow process of change that the plant had been working on up to that point. The plant may react by having to restart the process and seriously delay the scheduled maturation time.

I don't understand why it is that outdoor plants are not as sensitive to these nighttime interruptions. Perhaps it has to do with the unmatchable light intensity of the Sun. Stars, the moon and streetlights glowing through the low clouds over an urban area don't seem to hinder the outdoor plant all that much. For whatever reason, indoor plants tend to be ultra-sensitive to nighttime interruptions of light. So remember to make it dark and keep it dark.

-DJ Short

http://www.cannabisculture.com/v2/articles/1596.html

If Stainless lacks the reading comprehension to be able to understand the discussion, that's fine. He's so stuck on one particular definition of a word that he can't actually take part in the discussion. The irony is that word isn't even being used that way.

This is basic reading comprehension for any 101 level logic, comprehension or linguistics class.

 

[rasputin]

Complete darkness = no issues, ever. That's the truth.

If ya grow from seed or try out new clones the peace of mind of knowing the room is lightproof so regardless of individual plant sensitives they won't have any issues is worth the 10 minutes it takes to cover a pinhole leak or wrap an intake.

Lightproof things completely and you never have to worry about it.

 

[Capt.Ahab]

I firmly believe in making your room as dark as possible.
On the other hand Ive had outdoor plants on my back deck where the lights are on at night. The lighting doesnt seem to effect the outdoor plants at all, as far as I can tell.
Ive had outdoor plants stashed in the brush near my home that are exposed to some very bright motion activated security lighting that goes on and off at night. That seems to have no effect on the outdoor plants. They flower just as quickly and as well as those that are not exposed to light during the dark period.
Im not going to worry about a "pinhole" of light in my grow room. I really dont think it is enough to make a difference with most strains.

 

[mrcreosote]

Seems to me that DJ makes a logical inference about outdoor plants being used to high intensity sunlight not being susceptible to varying degrees of nightime light.
Since indoor gardens can rarely match that intensity it seems sensible that a much smaller amount of night period light could cause a disruption in a dark cycle.
Perhaps there is a ratio of PAR daylight to nightlight that, on average, plants can accept without disruption.

I know I'm not interested in doing hermie experiments on how to turn good genetics into schwag-weed.
This looks like a job for Bill Nye-The Science Guy.

 

[Homebrewer]

An interesting thing I noticed 2 months back while observing the progress of my own strain in flower was that the daily use of a weak flashlight to watch resin production seemed to induce some bananas compared to this round which I have not been watching at all. Even though I do have weak, ambient light coming into my room which has caused zero issues, the daily use of a weak LED light seemed to get a response from the plants.

 

[Phaeton]

I have had light leak issues affecting the plants, I fixed them. Two strains, only one had a problem.

Expert backup, yes indeed, experts come on every side of every fence, "unmatchable light intensity of the sun", try again, my room outdoes the sun's intensity very easily, care must be taken. Not arguing his point, just pointing out that even knowledgable folks says dumb things occasionally.

Anyhow, my sativa will react to any light intense enough to make out letters in a book, not bright enough to read, just make out the letters. The Northern Lights can be read to sleep and not care.

Since pretty much every comment made applies to some strain being grown how can intelligent people get angrily involved with a question not even having a single answer, or three? Sheesh whiz.

 

[Ur Humbl Nr8tor]

I think another thing to consider is the duration of darkness as well. In nature, marijuana has incremental daily changes to its light cycle. This natural light rhythm keeps the plants in tune with their cycles, even if a small amount of artificial light might shine on them. On the other hand, indoors, we typically force a plant to comply with a static amount of light and dark. No incremental change creates an artificial state that can be much easier to reverse. I have grown Sour Diesel and SD crosses indoors and some showed a minimal amount of sex reversal and I have grown crosses out doors that were rock solid. I have also grown out doors within 10 feet of porch and motion sensor lights as well as general city light, all without a problem. I wouldn't rule out DJ's considerations on light intensity either, but I have a feeling the natural cycle outdoors creates an enormous variable that is difficult to duplicate indoors. Those with light issues or finicky plants may want to consider a light cycle that more closely resembles the natural cycle.

 

[MPL]

I get that 100% lightproof is best for peace of mind... that's not the issue or the question or the point.

Bobby, you apparently don't understand what I'm trying to say and how definitions can and are used, and that's ok, because that's not the point here. As I said previously, your main idea was that you think absolute darkness is necessary, which is the information that was needed. Let's leave it at that.

While DJ Short is a badass pot grower, with more experience than most of us put together have, that doesn't make him infallible.

I contacted a former professor (PhD) about the issue. She doesn't know much about cannabis, but regarding photoperiods and sensitivity she said:

#1. It is extremely unlikely humans have been able to influence significantly the photosensitivity of cannabis in the very short time it has been grown indoors. In other words, stating that plants kept outdoors are more "accustomed" to the stronger sun and would suffer less from interruptions in their dark period because of this is most likely false.

#2. As has been stated, this can be very strain specific. Some, especially genetics lines (such as DJ Shorts) that have been inbred, bred over, backcrossed etc. usually show significant genetic weaknesses (frankly, according to all the biology I have read, 99% of cannabis "breeders" are idiots who don't know the first thing about genetics). Then, some strains may have grown in areas of the planet where at night there is very little light. Over thousands of years (not 50), these plants have adapted to that and may be more sensitive to light during their dark period.

#3. As a general rule in botany, total darkness is rarely ever necessary and in many cases is not desired. Commercial greenhouses (not necessarily cannabis greenhouses) don't generally bother unless there is a point light source that allows direct, uninterrupted light into the area. While she wasn't specifically referring to cannabis greenhouses, the concept is the same and the biology between cannabis and other similar plants is not that different.

She mentioned that a lot of research done in commercial greenhouses indicates supplementing with a source of "moonlight" increases health, yield and overall quality.


I bring this up because a lot of people spend a lot of time trying to design absolutely dark rooms for their plants. While I do agree that for peace of mind, this is the best way to do it, I don't believe it is completely necessary and, depending on the circumstances, may in fact be a waste of time or detrimental.

So far in my current cycle I've got 4 strains going, all of which are exposed to semi-direct light from my mom and veg areas, as well as overhead lighting so one can generally see to work in the grow area. I have not repaired any of the pinholes in the current flowering tent and I am using the big halfmoon passive air intake that is built into the side. 3 weeks or so left to harvest and the only strain to show hermies is a bagseed plant from my father-in-laws last crop before he died. Ironically, it's farthest from any source of light and receives the least light of all my plants. This plant's genetics are known for hermies so this isn't unexpected.

My legit DJ Short BB plants (2x), my Jack Herer plants (gifted clone, it's GOOD) and my two Orchid plants are heavy and sugary. No seeds, no hermies. My larger BB receives enough light that I can make out minor details in the bud during the dark period and is one of the healthiest plants I have right now.

I have opened my tent now 3 times in the middle of the light period, exposing my plants to direct overhead light, a LED MagLite and a rack of T8s over my moms.

I'll report my results when I harvest.

Disclaimer: I did not set out to test this, so all of my information is my own experience and is anecdotal by definition. There are other valid opinions just in this thread alone. If you are worried about light during your dark period, then the best thing to do is set everything up to be completely, 100% lightproof.

 

[MPL]

I need to look into this more, but apparently commercial growers of other photoperiod sensitive plants are testing moonlight supplementation during dark cycles and are having great success with it.

Your post agrees with what I have been able to find on this topic so far.

I respect DJ for all his work and accomplishments, but he is far from the most knowledgeable person on plant biology in general, and as far as I have ever been able to tell from his articles he has a limited grasp on biochemistry as well.

DJ, for all his badassness (I grow his gear, and one of my favorite strains ever is his BB), is a hobby cannabis breeder. The reason I say this is because no one in the world, as far as I can tell, has a facility capable of doing real, documented, controlled breeding (look at tulips, or apples, or tomatoes). The reason is obvious - it's illegal in most places. That doesn't change the fact that our base of knowledge for cannabis is relatively small, and in my experience growing for the past 5 years I am learning that the majority of the truisms I had been taught are outright falsehoods and myths, or only partially true.

I think absolute dark for the dark period is one of those myths. The reason is that for someone growing secretly, or semi-secretly, or for someone trying to grow commercially in a grey area of the law (Colorado, CA etc.) it's easier to just make it completely dark than risk any part of the crop. Those folks aren't interested in furthering the scientific understanding of the cannabis plant, nor are they interested in doing any experimentation or research themselves. Most of the time, the growers I know prefer to stick with what works and are some of the most risk averse people I have ever met in my life. Right now, all things considered, that's probably not a bad thing, but in the end it does all growers a disservice.

I think another thing to consider is the duration of darkness as well. In nature, marijuana has incremental daily changes to its light cycle. This natural light rhythm keeps the plants in tune with their cycles, even if a small amount of artificial light might shine on them. On the other hand, indoors, we typically force a plant to comply with a static amount of light and dark. No incremental change creates an artificial state that can be much easier to reverse. I have grown Sour Diesel and SD crosses indoors and some showed a minimal amount of sex reversal and I have grown crosses out doors that were rock solid. I have also grown out doors within 10 feet of porch and motion sensor lights as well as general city light, all without a problem. I wouldn't rule out DJ's considerations on light intensity either, but I have a feeling the natural cycle outdoors creates an enormous variable that is difficult to duplicate indoors. Those with light issues or finicky plants may want to consider a light cycle that more closely resembles the natural cycle.

 

[abellguy]

I must be really overly anal I cover the LEDs on my C.A.P. timers with tape lol

 

[MPL]

I used to do the same thing. Remote temp probes would get black duct tape over the LED. Intakes used to be a hassle (I use 20"x20" HEPA filters on my room intake) to lightproof (would build light traps that could house the filters since they don't make a return or register that'll block light too), duct work had to be perfect etc.

Then I got a tent.

Ultimately, the reason I started looking into this is because of my tent. There is no practical way to really lightproof it, especially the passive intakes. The amount of work to block every pinhole of light would be immense and I don't like unnecessary work (it eats into profit and I'm lazyish).

So, I called greners (where I bought it) and Hydrohut (the mfg.) and asked what they thought. They convinced me to try a test cycle (which is why this round has so many different strains and is in soil) to see how the light affects my plants. They expected that I wouldn't have any problems as long as the rest of my grow was solid. That's proven to be the case with 2ish weeks left to harvest. No issues whatsoever from light stress.

I must be really overly anal I cover the LEDs on my C.A.P. timers with tape lol

 

[abellguy]

It is a really good point for sure, I don't know anybody that is growing in a tent that the room isn't dark around it so any light cant get in cause there is no source for it. A test would reveal weather or not it truly makes a difference but that would be strain dependent I think for sure cause some seem like they will hermi if you just sneeze in their direction with your mouth covered!

 

[MPL]

Very true. I don't keep strains that hermie at the slightest bit of stress. It's too stressful! haha pun intended laf

I'll post my results after I harvest, but usually by the time you are this close to harvest if you are going to get hermies you already have.

I have made little effort in keeping the tent in a dark area of my grow, nor have I made any real effort to be careful about light contamination. We'll see how it turns out.

I doubt many others would be willing to risk a 4x4 table worth of plants to figure this out, but I am.

It is a really good point for sure, I don't know anybody that is growing in a tent that the room isn't dark around it so any light cant get in cause there is no source for it. A test would reveal weather or not it truly makes a difference but that would be strain dependent I think for sure cause some seem like they will hermi if you just sneeze in their direction with your mouth covered!

 

[abellguy]

Will be looking forward to the results of the test for sure, and hopefully the "risk" you are taking with the 4 by 4 ins't to big of one in the end.

 

[crisscross]

#2. As has been stated, this can be very strain specific. Some, especially genetics lines (such as DJ Shorts) that have been inbred, bred over, backcrossed etc. usually show significant genetic weaknesses (frankly, according to all the biology I have read, 99% of cannabis "breeders" are idiots who don't know the first thing about genetics).

Yup. I just found out that nearly 80% of all statistics are made up...only 6% of people know that. don't make stuff up. you sound articulate but making up statistics based on here say is silly. yes, I used the word silly. I used that silly word just to make an impression on you and all the other silly people that make up stats.

anyways I have a cheap crappy made in China tent that has leaks on the zippers. thing is that the tent is in my garage where ONE small cfl is on all the time. it's about 8' away, and I have small pin hole leaks (plural). Apparently my tent is doing a good enough job because there are no bananas. Or I'm just lucky.

luck is luck and science is science. do a side by side experiment and let us know what you come up with. then do it again. and again. then have friends do it. then have them do it again. then, and only then will you have enough information to create a hypothesis.

good luck

 

[MPL]

If you say so. I'm not making anything up, and stating that I am just because you think that I am makes you no better than what you just described.

I think I was quite clear when I said these are my personal experiences and that they are anecdotal. Yup, that's pretty much the sum of it.

You seem to have somehow assumed and then implied that I am claiming to be doing some kind of placebo-controlled, double-blind study regarding this or some other nonsense and then claiming that I have the absolute, black and white, infallible scientific statement or some such. I'm not. I threw a bunch of plants into a tent and then didn't bother with any lightproofing other than what came with the tent and called it a day. I then researched the topic, found lots of very interesting information on photosensitivity of other plants, applied a little bit of logic and reasoning (plants are never, ever exposed to 100% darkness in nature, not ever. How luminous is the moon? Well most likely plants can take some light then etc.) and came up with a TOPIC OF CONVERSATION, thus this thread.

I BELIEVE that ABSOLUTE DARKNESS is NOT absolutely necessary. I have SOME research that shows this for other plants, I have SOME ANECDOTAL evidence of my own and a little from others and that is all I have ever claimed.

I do, however, have more than enough evidence to suggest that this topic is worthy of more time and energy than it has gotten. It's obvious that it isn't as simple as "the lights are either 100% on or 100% off", especially if there is some benefit to be gained, as has been suggested.

I'm not sure what the hell you had going through your mind when you posted that drivel.

Yup. I just found out that nearly 80% of all statistics are made up...only 6% of people know that. don't make stuff up. you sound articulate but making up statistics based on here say is silly. yes, I used the word silly. I used that silly word just to make an impression on you and all the other silly people that make up stats.

anyways I have a cheap crappy made in China tent that has leaks on the zippers. thing is that the tent is in my garage where ONE small cfl is on all the time. it's about 8' away, and I have small pin hole leaks (plural). Apparently my tent is doing a good enough job because there are no bananas. Or I'm just lucky.

luck is luck and science is science. do a side by side experiment and let us know what you come up with. then do it again. and again. then have friends do it. then have them do it again. then, and only then will you have enough information to create a hypothesis.

good luck

 

[Jamorg13]

I aim for complete dark(why not) but Iv got a tiny bit of light. Iv gone to my outdoor on a full moon and I COULD read a book,nit was really bright. And I didn't have any problems