Why go 24 hours lights on??

[Marshall]

i spent a good amount of time last night reading this whole thread, and this morning reading another unrelated thread. I will go back later and read some of the links spurr.

Spurr, it may be light saturation. I was at Borders picking up a couple books, and I was glancing through some of the MJ books, and I remember reading something about the plants stop photosynthesis at 5500 lumens. I am certainly not saying it is right or wrong. I am almost positive thats what it said.

So you agree at a point photosynthesis will slow down and light may be wasted? It just can not be measured in lumens?


I have heard that cannabis can not process all the light thrown at it at once, that is why light movers are effective



This is all very interesting, hope I can keep up

 

[bobman]

buddy your talking in circles. What is the dli of a 1000 watt hps over 24 hours in the 400-700 nanometer range. You do not even know yet you make these claims.

 

[bobman]

put up numbers/data mr wizard.

 

[rocket high]

im staying impartial as i dont want my ass kicked by either of you ... but im am reading it for educational purposes as well as the backhanded and obvious insults

 

[spurr]

Spurr, it may be light saturation. I was at Borders picking up a couple books, and I was glancing through some of the MJ books, and I remember reading something about the plants stop photosynthesis at 5500 lumens. I am certainly not saying it is right or wrong. I am almost positive thats what it said.

You are correct that is what was claimed, but they didn't use proper testing protocols to make such a claim. That is why I state the claim is wrong.

So you agree at a point photosynthesis will slow down and light may be wasted? It just can not be measured in lumens?

Yes, and yes

I have heard that cannabis can not process all the light thrown at it at once, that is why light movers are effective

Not to my knowledge, I call that BS. If we provide too much irradiance (i.e. PPFD) then yes, they can't use all the light, but that is the same thing as (exceeding) light saturation. Using a light mover won't help if a grower is providing too much irradiance because PPFD is measured per second. And if a grower is providing ideal, or less than ideal irradiance, a light mover also won't help in terms of "cananbis [that] can not process all the light thrown at it". Cannabis, and other plants, can process all the photons provided (with caveats of photon reflectance, transmittance, sunfleck, etc.) as long as we don't provide too many photons and other eviron variables are in order, like Air-to-Leaf Vapor Pressure Deficit.

This is all very interesting, hope I can keep up

You're doing great so far!

 

[VerdantGreen]

buddy your talking in circles. ....

bobman he is talking in circles because you are refusing to grasp what is being repeatedly explained to you.
just give it up. its very clear that you are now just arguing for the sake of it and also being rude and abusive.

it's your choice where you put your timer or lack of, but if you want some suggestions...

 

[Rumpleforeskin]

Opposing viewpoint was censored.

 

[spurr]

buddy your talking in circles. What is the dli of a 1000 watt hps over 24 hours in the 400-700 nanometer range. You do not even know yet you make these claims.

You can't find DLI in that instance because you don't know the irradiance. You need the irradiance (amount of photons at canopy; i.e. PPFD) to find DLI, plus the hours per day. The distance to canopy and wattage of lamp is irrelevant except that they both affect irradiance (closer to canopy and higher wattage = high irradiance).

 

[rocket high]

educational and funny you cant ask more than that ...brill

 

[spurr]

im staying impartial as i dont want my ass kicked by either of you ... but im am reading it for educational purposes as well as the backhanded and obvious insults

Haha, OK, good point

"backhanded...insults" like when I refer to "bobman" as "boobman"?

 

[rocket high]

ok the obvious insults .... im a sucker for insults

 

[Rumpleforeskin]

most major MJ publications who agree with you that 24 hours of lights on is the "best" way to veg plants

UNTRUE, I have found a famous marijuana grower that agrees with spurr.

Ladies and gentlemen, I give you Mr.Green from the "I Grow Cronic" video.



He also agrees we should spray club-soda on our plants.

 

[spurr]

<face palm>

You just proved my points for me...

For anyone who does want to calculate your DLI and/or PAR (I can't believe I've wasted 20 minutes on this, ugh), all you need is a light meter (I have a fancy schmancy digital one and could do this if anyone wanted) and a calculator (according to the attached link, which seems legit to my uneducated self as it's a university publication).

Page 4 of the link:

http://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf

Maybe you missed the many times where I explained why foot candles (FC), lumens and lux are not light measurements for plants? Using them to measure light for plants is a fail because they are weighted, and PPFD is not. You still don't understand the basics.

You also failed to read this thread because I already posted that PDF, and it seems you didn't the PDF either:

Daily light integral

Daily light integral (DLI) is the amount of PAR [i.e. PPFD] received each day as a function of light intensity (instantaneous light: μmol·m-2·s-1 [i.e. umol/m^2/second; just like I wrote!]) and duration (day). It is expressed as moles of light (mol) per square meter (m-2) per day (d-1), or: mol·m-2·d-1 (moles per day). [i.e. moles/m^2/day; just like I wrote!]

And notice the PDF also states what I wrote: that one MUST convert from foot candles, or lumens or Lux to PPFD, and THEN use PPFD to find DLI! Further, the author also states, albeit less obviously and less correctly than I did, that you can't convert FC to PPFD with accuracy because of different SPDs (Spectral Power Distribution) of lamps. Re: the conversion factor he provided of 0.13 FC to 1 PPFD (which is wrong, see below)

The author gave a conversion factor of 0.13 FC to 1 PPFD, but that's wholly incorrect. That conversion factor is closer to correct for older-style (traditional) HPS lamps, but only when they are brand new, because as lamps age the SPD changes, and thus the conversion factor of 0.13 FC to 1 PPFD would be wrong; just like I wrote. We use HPS lamps with different SPDs than traditional HPS used to find the conversion factor of 0.13 FC to 1 PPFD, especially "enhanced HPS" like Hortilux Super-HPS, etc. Thus, you can't use the conversion the author gave of 0.13 FC for 1 PPFD for an ACCURATE conversion using today's high tech cananbis growing HPS lamps.

FWIW, the great Japanese plant biologist Katsumi Inada wrote a online conversion tool for many various lamps (MH and HPS) from FC and lux to PFPD. However, even K.Inada's work, that the author of the PDF used for the conversion factor of 0.13, is no good for today's lamps due to the different SPDs!

Dude, start reading what I wrote, and thinking about it, instead of just tying to prove me wrong...which you have failed miserly at this whole time

Knna wrote a good spreadsheet for converting lumens/lux into PPFD using the SPD of the lamp, it's over at gardensecure forum. Look it up if you want to learn more than you now know, his spreadsheet is WAY better than using the PDF you uploaded. However, even with Knna's spreadsheet the error margin will be at least 5-10%, and his spreadsheet will only work with BRAND NEW lamps because the SPD changes as the lamp ages!

Man, is there an echo in this thread!?!

Table 1. Converting Foot-Candles to PAR and DLI

This table shows how to calculate from foot-candles to PAR (µmol.m-2.s-1), and from PAR to daily light integral [DLI (mol·m-2·d-1)] for sunlight and high-pressure sodium lamps (HPS). Note that the conversion factor from foot-candles to PAR depends on the light source.

You failed, yet again, in your quest to prove me wrong. Just give up.

 

[bobman]

bobman he is talking in circles because you are refusing to grasp what is being repeatedly explained to you.
just give it up. its very clear that you are now just arguing for the sake of it and also being rude and abusive.

it's your choice where you put your timer or lack of, but if you want some suggestions...

Verdant nothing is being explained thats the problem with his points. Just random numbers are being thrown out that have nothing to do with proving facts. As bob smith said DLI is simple to calculate once you have a light meter. I just wanted to expose this guy using science because I did not before. Take two minutes of reading and you can figure out yourself this guy has no clue. People like this are dangerous and must be exposed. Spurr take your PPFD, DHL and more importantly DLI-PPFD numbers that you are magically pulling out the air for the environment we grow in and go win yourself a Nobel. I know what these terms mean now and you are not using data related to what we do.

 

[VerdantGreen]

WHO WOULD YOU BELIEVE IF YOU WERE IN MY SHOES?

if you look at this thread, it seems sam skunkman is pretty convinced by spurr.
https://www.icmag.com/ic/showthread.php?t=193173&page=3

please try and let spurr post his info as there are many folks here who value it. he is being attacked and abused in this thread far more than he is attacking or abusing anyone else.

VG

 

[VerdantGreen]

please accept my apologies Bob Smith. i was getting my bob's mixed up.

i was really referring to the general hostile nature of some folks who seem to react really badly to someone who is trying to apply scientific principles to growing cannabis - personally i see it as a very useful addition to any community of growers.

VG

 

[spurr]

please accept my apologies Bob Smith. i was getting my bob's mixed up.

Ditto, I thought I was responding to a post by boobman (aka bobman), not Bob Smith, my bad for using a terse attitude toward Bob Smith that was meant for boobman.

 

[Frozenguy]

Its proven by professional researches that plants do derive benefit from darkness, or a lack of light.

They collect energy using certain proteins during day, then switch to a different set of proteins (normally cued by a lack of light) to use that collected energy and focus it all on growing and cell repair. Its a very efficient way to maximize growth in ALL ASPECTS, not just height, but in cell quality among MANY other things.

When you go 24 hour lighting, it tries to collect energy and grow, something it can't readily do exactly at once so it has to start trying to multitask. It wasn't designed to multitask. It ends up growing taller, faster, but with a weaker foundation.

You will get a plant to 24" (or whatever height you want) faster, but with less then ideal results in other categories.

-At least 4 hours of darkness lends to an overall better plant.
-24h lighting just leads to a faster, but "inferior" growth. You can't even see it because the inferiority resides mainly within the cell's health and cell's physical structure (bloated, weak).

 

[spurr]

Proved what points, dude?!?!?! (WTF???)

Why are you so defensive and angry?

I am not angry, but I am terse and tired of re-explaining things and the never-ending challenges on things that I am right about. Esp. when the challenger tries to show what I wrote is wrong, when in fact, they cite material that shows what I wrote is correct.

I thought you were boobman (aka bobman), my bad. I thought I was posting to boobman who is as relentless as he is wrong, sorry for mixing both of you up.

I simply took a quote from you and explained in AS SIMPLE OF TERMS AS I COULD (as an aside, I've always felt that the people who understood things best were those who were able to simplify it so anyone could understand it........just sayin') and linked people to an article explaining how to calculate it.

You stated earlier in the thread that you would explain to anyone who asked, but you never did (to my knowledge), so I took the initiative and explained it to people.

You are correct, I had yet to explain how to convert from FC or lumens or Lux to PPFD. The reason is each different lamp model has a different SPD, thus, the 0.13 FC conversion (and any other standard conversion) is not accurate enough to provide an accurate PPFD.

Given all issues I listed in my last post about trying to convert FC or lumens or Lux to PPFD I hope you can see why I am very hesitant to do so. It just isn't' accurate enough, you need to assume at least a 10-20% error margin is using a static conversion factor of 0.13 FC to PPFD under new HPS lamps vs. traditional HPS lamps. That is why I wrote the only accurate way to convert from FC to PPFD is using a spectroradiometer to make custom SPDs to un-weight the FC reading.

Look into Knna's spreadsheet at gardenscure (link), he complied a decent list of lamps and their PPFD (using PAR watt/m^2 and spectral output from the lamp's SPD). And even the lamp's Quantum Flux Density, i.e. weighting PPFD with K.McCree's Action Spectra of Photosynthesis. I can also provide the resources (math and such) Knna used to make his spreadsheet.

The problem with Knna's spreadsheet is multifaceted, entailing at least:
​

(1) the PPFD from SPD of each lamp can't be compared to PPFD from SPDs of other lamps unless we know the "absolute irradiance calibration" of each spectroradiometer used to make the SPDs.

(2) the SPD data used by Knna for his spreadsheet are error prone because to use it we have to count pixels of SPD lines per wavelength (computer screen); i.e. human error.

(3) the SPD of a lamp will change depending upon the ballast and reflector used, thus, unless all lamps use the same ballast and reflector the SPDs can't be compared, nor can the PPFD from the SPDs. This is why SunPulse lamp company (link) does not provide SPDs.

(4) the SPD changes as the lamp ages, thus if you find the PPFD of a lamp using Knna's spreadsheet that PPFD datum will only be good for a small time frame.

Also, if you use FC to find PPFD that PPFD datum will only be worthwhile (caveat is that it's incorrect to start with) from a short time, and ONLY when the lamp is brand new because the SPD changes as the lamp ages and thus the conversion factor of FC to PPFD changes, it's not static.

(5) the SPDs are not always found with the lamp the same distance from the spectroradiomter. Thus, PPFD from SPDs of different lamps can't be compered unless we know it's from the same distance. Also, if you hang your lamp at a different distance than used for the SPD, the PPFD datum will be wrong.
​

What people should do is simply use a quantum sensor to find the PPFD under their lamp, then no conversion is needed:

The least expensive PPFD meter (i.e. quantum sensor) is ~$200 from SpecMeter (link), but that is a rather inaccurate unit because it doesn't provide sufficiently equal unweighted wavelengths over the whole PAR range. The better option costs ~$1,000 and is from Li-Cor, their quantum sensor is top notch (~$300) and it is very accurate (link), one also needs the data reader (~$600) from Li-Cor (link).

FWIW, when finding PPFD, one needs to take measurements at least every 3" over a meter squared. That means 144 measurements (every 3" length-wise and width-wise over 3'x3'), add them together and find the average, to find PPFD.

And I saw that you linked to that pdf earlier, but I doubt most people read each page of the 500 links that you've provided, so I provided one link to help with one calculation (I like to K.I.S.S.).

FWIW, I don't need to prove you wrong - your insecurity and troll-ish behavior (as evidenced by you being banned for a time) should do that for anyone reading the thread.

Me being banned was not due to "troll-ish" behavior, it had to do with me calling out a mod.

Again, no offense, but I'm gonna go with a link from Purdue University which states that foot candles are perfectly fine for calculating DLI than some unknown person on the Internet

Do as you wish, but don't think for a second your figures are correct, not by a LONG SHOT. If I contacted the author of that PDF he would agree with me 100%. I am not making this stuff up.

The simple fact is you can not convert from FC to PPFD with any degree of worthwhile accuracy, esp. if the lamp is not brand new and if you're using a digital ballast (both of those factors affect the SPD, which in turn, affect the conversion from FC to PPFD).

...who (admittedly):

1) Is smarter than anyone in the field he's met
2) Has only been at this for a few years
3) Disagrees with most major MJ growers and authors
4) Acts so childishly that he gets banned for being in flame wars
5) Is doing research no one else in the field has attempted before
6) Has no academic credentials to speak of

1) I didn't say that, I said I knew more, which is true. Even in all the various cannabis forums I have been a member of. It's not bragging, it's just stating a simple fact as I see it.

2) "At what"? I've been growing for about 20 years. But only been studying these topics from about 4 years, and that's plenty of time to know what I'm talking about.

3) Yes I do, and I'm right too. Please stop using logical fallacies like you just used, ex. "appeal to popularity" and "appeal to common practice" and "appeal to belief"...seriously, learn what logical fallacies are, and why they suck, and why you shouldn't use them.

4) Patently false, get your facts straight and stop making assumptions and telling lies.

5) Yes, and you should be thankful for that...I assume you'll be my books

6) No advanced degrees (yet), but so what? Advanced degrees are pretty worthless in plant biology if a person has the ability, money and willingness do without them. Now, chemistry is a different story, etc.

Spurr, given the evidence presented to me, WHO WOULD YOU BELIEVE IF YOU WERE IN MY SHOES?

Umm, me of course...as do many, many people who are in your shoes

 

[spurr]

Hey FG,

I noticed this same post in the other thread, so I thought I would post my same response here.

You will get a plant to 24" (or whatever height you want) faster, but with less then ideal results in other categories.

-At least 4 hours of darkness lends to an overall better plant.
-24h lighting just leads to a faster, but "inferior" growth. You can't even see it because the inferiority resides mainly within the cell's health and cell's physical structure (bloated, weak).

We can all agree that 24h veg lighting grows faster, but that is not much when taking into account other factors of the switch.

Claiming 24 hours of light leads to faster growth is an inaccurate statement because it lacks the most important piece of info: DLI (Daily Light Integral), i.e., the sum amount of photons within PAR range in a meter^2:

I agree with most of your claims, and you seem like a really smart person, but the fact is plants (C3) grow the most at night and very early morning (i.e. the greater cellular growth and repair). Thus, if we provide the same DLI in 18 hours as we do in 24 hours, the plants under 18 hours of light will grow faster than those under 24 hours of light.
​

That is the point most people are misunderstanding, it's not about hours per day, it's about photons per day.