Why go 24 hours lights on??

[DHF]

JJ....I truly apologize for that particular statement as I was trying to impart experience over so-called text , but not for another word said in this most pitiful excuse of a self-proclaimed Grow God that`s been banned from all the older more experienced grow sites almost as fast as he joined and started spewin all his theoretical bullshit and shovin it down everyone`s throat expecting us all just ta swallow instead of spit........

There is such a thing as "opinions may vary" huh ?.........

Nuff said.....DHF.......

 

[spurr]

Nuff said.....DHF.......

I hope so, please either stay on topic or stop posting.

 

[JJScorpio]

And for the record, I don't knows whose opinion is what.

We get reported posts and I glance through the thread and clean up rude, inciteful posts. I couldn't tell you who has what opinion in the matter..... And if I did, I don't think it would be worth "censoring" as you say.....

 

[spurr]

@ all,

I made a typo in the post where I uploaded the following paper, the Lux exceeded 12,000; not 120,000...ooops!

"Photosynthesis and Cannabinoid Content of Temperate and Tropical Populations of Cannabis sativa"
F.A. BAZZAZ, D. DUSEK, D.S. SEIGLER and A.W. HANEY
Biochemical Systematics and Ecology 1975, Vol. 3, pp. 15-18

Results

Light saturation curves for the net photosynthesis of four populations were similar or all populations under both growing conditions (Fig. 1). Saturation was not reached even at 12,000 lux indicating that all populations belong to the sun plant group.

 

[DHF]

What`s to post as far as staying on topic about 18/6 being optimal for production........bar none.....it`s already been tested time and again......

Good luck with your thesis and mid term project on "theoretical" yield expectations of cannabis based on your thoughts on how yields oughta be based differently from time tested procedures......

There is no topic to this thread anymore...........Please shitcan this disaster........

Again I apologize for my behavior , but when I see smokescreens and buncha verbal bullshit overshadow watts per sq ft and proper environment that "actually" DO have direct effect on yield and production , I haveta step up and voice my opinion based on experience , and not conjecture.......

Kill this thread ......Guaranteed Gojo starts another 1 on somethin that only he knows the answers to ............Been there , done that a few times at other places .........

Peace....DHF..........

 

[DHF]

It`s no different from his one-sided vapor deficit thread at the Cabana where I agreed with his "book - gleaned" knowledge on 70% relative humidity being optimal for veg growth all the way through end of stretch , till needing to drop it as much as possible for fear of PM and budrot during late flower.....

Then , the claws came out........Proved to me he was a researcher and not a grower.........

Wish all could be dicussed amicably without the "absolutes" Gojo says are the way , the truth , and the light .......

Get a grip..DHF.........

 

[spurr]

Going off of your assertion that plants perform best at 1500 DLI (although one of the studies you linked to said 1500-2000, and they only enriched with CO2 to 750PPMs whereas I go to 1500PPMs, but that discussion is dead)

I never wrote 1,500 DLI; I wrote 1,500 PPFD, and 46-48 DLI

Also, its obvious you didn't read any of the four papers I uploaded that all found ~1,500 PPFD as ideal. And that most probably all drug bio-type species/races/varieties under Cannabis spp. likewise do best around 1,500 PPFD in terms of rate of photosynthesis, etc.

Also, the last paper I uploaded that used Lux, fond all four races studied (both temperate and tropical ecotypes) benefit from similar irradiance. If you only want to use a light meter that is not made for plants, then use Lux, not foot candles. Read the paper I uploaded titled "Photosynthesis and Cannabinoid Content of Temperate and Tropical Populations of Cannabis sativa" for more info; if you want to waste your time on the "boring" studies I provided...

I don't feel like commenting on the rest of your message, I know you really couldn't care less what I have to say.

 

[spurr]

It`s no different from his one-sided vapor deficit thread at the Cabana where I agreed with his "book - gleaned" knowledge on 70% relative humidity being optimal for veg growth all the way through end of stretch , till needing to drop it as much as possible for fear of PM and budrot during late flower.....

Then , the claws came out........Proved to me he was a researcher and not a grower.........

Wish all could be dicussed amicably without the "absolutes" Gojo says are the way , the truth , and the light .......

Get a grip..DHF.........

lol, just for you: "VPD and nutrients absorption". That is the current thread about VPD here at ICmag, and guess what, I uploaded the full thread I wrote from TCC

I have every single thread from TCC that I made and in which I participated, in full text. I plan to upload them to Freenet, or mabye Bittorrent, so anyone can read them,s o hopefully my efforts will not be in vain from TCC.

I never wrote "70% RH is ideal", you are so disingenuous it's not even funny. I will defer to the tread I linked to above, where people can read what I wrote here, and there.

I will not be baited into being rude to you.

 

[mrwags]

What kills me is when a group of stoners get together on the internet and then tell each other what is best for the OTHERS room with out ever stepping in it or usually knowing nothing about it.

Different rooms and different areas have changes that can and will make things different for EVERYONE. To dog out a mans style without EVER partaking in his labor of love is BULLSHIT and simply wasted words and usually wasted energy.

JJ doesn't have time to babysit and will usually only get involved when someone snitches and reports a post. This in turn send up a red flag and he comes in to see what the fuss is about. So if he gets one and not the other congrats you escaped because you didn't get snitched.

So if you all fell a need to bully each other please you the pm system because it's starting to stink in here and with all these ego's I don't think were gonna have enough room.

Just Funnin

Smoke a bowl of something and always remember it's the freakin internet you silly ninny's.


Have A Great Day
Mr.Wags

 

[VerdantGreen]

i would appeal to the mods not to bin this thread as it contains a lot of very useful information for growers that are open-minded enough to learn something. it would also play into the hands of those few posters who are clearly trying to disrupt the debate with personal attacks.

its pretty clear that the posts getting removed by mods are the ones that are either abusive/rude or off topic. i had a couple removed that were very polite - but admittedly off-topic.

spurr im very glad to hear that you kept your posts from TCC, i havent even been back since they deleted you - i thought that was a criminal thing to do, so much info there for people to read or ignore - whatever they prefer.
i dont want a 'social club' website where everyone is just patting each other on the back, i want to learn (and teach)
maybe some of those posts would be suitable for the new forum??

VG

P.S Bob Smith you should check the TOU - posting the contents of PM's in open forum is a big no-no

 

[SumDumGuy]

I'm going to unsubscribe from this thread. You guys and gals are all great people!! Do what works best for you. I love 24/0 and that's just what it is. Do what you like and smoke your home grown with a smile . Peace, love and hugs with lots of buds..

 

[bobman]

Hey Spurr i read the paper you keep quoting saying 48 DLI for cannabis from the university of miss. That was for a flowering cannabis plant. Would that not mean a vegging cannabis plant would take more DLI. Curious to your response not trying to start a war. Also you still have not shown a paper that states the best DLI for a vegging marijuana plant. Science is for the skeptical mind until proven. I have stated many times that I would love to lower my electric. But I run very tight cycles and can not risk growth.

 

[spurr]

Hey Spurr i read the paper you keep quoting saying 48 DLI for cannabis from the university of miss. That was for a flowering cannabis plant. Would that not mean a vegging cannabis plant would take more DLI. Curious to your response not trying to start a war. Also you still have not shown a paper that states the best DLI for a vegging marijuana plant.

----------------
I might edit the following post later today for clarity and typos, I wrote this pretty fast and I don't have time to fully check it now. But it should be correct...
----------------​

I never uploaded a file showing 48 DLI for cananbis is a goal, so you couldn't have read it. I don't know of any studies on cannabis looking at DLI; which is why I plan to conduct my own studies on cannabis and DLI, etc., this coming year.

We can use PPFD to find DLI, and use DLI to find PPFD:

1. DLI (mol/meter^2/day) = (PPFD*3,600*daylength)/1,000,000
2. PPFD (umol/meter^2/second) = ((DLI*1,000,000)/daylength)/3,600

There are no studies looking at DLI for cannabis AFAIK. DLI depends upon hours per day and PPFD. However, there are many studies looking at ideal PPFD for cananbis. We could take the ideal PPFD for cannabis, ~1,500, and simply use that to find DLI for a plant providing 1,500 PPFD all day, but if we did that we would be over-saturating the plant with photons over the whole day, and in turn, cause photoinhibition.

Considering once PPFD (for cannabis) drops below ~1,000 the rate of photosynthesis (Pn) drops quite a bit, using at least ~1,000 PPFD all day is a good goal. I think using ~1,000 to ~1,3000 PPFD all day is the best choice. I plan to test that DLI on Pn and net rate of photosynthesis (Pnnet), etc., for cannabis this coming year.

I already wrote about how/why I found the 46-48 DLI (using natural PPFD bell curve data from here), for a 12 hour day. 48 DLI equals ~1,111 PPFD in 12 hours. In nature, DLI can be as high as 60, but that's quite high for flowing and I wouldn't use it, nor suggest it, until I had a chance to test it, and test the Pn, Pnnet, etc., under a DLI that high for flowering.

During veg and pre-flowering plants often have a higher rate of photosynthesis (they are able to use greater instantaneous photons as PPFD and net daily photons as DLI) due to more and younger leafs (younger leafs photosynthesize better than older leafs). During flowering rate of photosynthesis is often reduced due to the changing needs of the plant, i.e. going from growth (veg/pre-flowering) to reproduction (flowering). Flowers themselves also photosynthesize, but not as well as leafs.

In the following example we can see that using ideal PPFD for cannabis (~1,500), all day, gives way too much total light (DLI). That is why I used a natural bell curve of daily PPFD found in nature (peaking at ~1,800 PPFD around noon) to come up with 48 DLI for flowering.

(DLI datum is rounded):

• 1,500 PPFD for 12 hour daylength = ~65 DLI
• 1,500 PPFD for 18 hour daylength = ~97 DLI
• 1,500 PPFD for 20 hour daylength = 108 DLI
• 1,500 PPFD for 24 hour daylength (no dark period) = ~130 DLI

In the following example I work backwards from the highest DLI found nature (~60), and from 48 DLI (my claim for cannabis in flowering) using various daylengths.

(PPFD datum is rounded):

• 60 DLI for 24 hour daylength (no dark period) = ~695 PPFD
• 60 DLI for 20 hour daylength = ~833 PPFD
• 60 DLI for 18 hour daylength = ~926 PPFD
• 60 DLI for 12 hour daylength = ~1,389 PPFD

• 48 DLI for 24 hour daylength (no dark period) = ~556 PPFD
• 48 DLI for 20 hour daylength = ~667 PPFD
• 48 DLI for 18 hour daylength = ~741 PPFD
• 48 DLI for 12 hour daylength = ~1,111 PPFD

So, after looking at all those figures, and with the knowledge that 1,000 to 1,300 PPFD is a good goal (less than 1,000 PPFD reduces Pn too much IMO, and more than 1,300 PPFD over the whole day can also reduce Pn too much IMO), we can use ~1,000 to ~1,300 PPFD to find DLI for various daylengths in veg. We also need to keep in mind that in nature, ~60 DLI is the highest normally found, and that > 60 DLI is too much for most 'sun loving' plants to keep Pn and Pnnet high all day. Thus we should try to keep DLI closer to what other sun loving plants do well under, and that is 60 DLI (or less). That means, after looking at the figures below, we should try to use at most 1,000 PPFD for 18 hours. However, I for one have tested 16/8 and 17/7, and both worked very well when I kept PPFD high. Thus with 16/8 or 17/7 we get the best of three worlds: high PPFD, high DLI and a dark period.

• 1,300 PPFD for 16 hour daylength = ~75 DLI
• 1,300 PPFD for 17 hour daylength = 80 DLI
• 1,300 PPFD for 18 hour daylength = ~84 DLI
• 1,300 PPFD for 20 hour daylength = ~94 DLI
• 1,300 PPFD for 24 hour daylength (no dark period) = ~112 DLI

• 1,000 PPFD for 16 hour daylength = ~58 DLI
• 1,000 PPFD for 17 hour daylength = ~61 DLI
• 1,000 PPFD for 18 hour daylength = ~65 DLI
• 1,000 PPFD for 20 hour daylength = 72 DLI
• 1,000 PPFD for 24 hour daylength (no dark period) = ~87 DLI

Considering all the info above, I think 46-48 DLI for flowering (~1,065 PPFD for 12 hours and ~1,111 PPFD for 12 hours, respectively), and 58-61 DLI for veg (~1,000 PPFD for 16 hours and ~1,000 PPFD for 17 hours; respectively) are goals to be considered.

I plan to thoroughly tested various cannabis races and varieties by tracking their Pn and Pnnet, etc., under PPFD and DLI I listed as goals above. But for now, there are no studies looking at DLI for cannabis, so I used data from other studies on similar C3 plants (i.e. sun loving), and DLI/PPFD data from Hawaii, to find the goals I wrote above.


FWIW, I uploaded an older article by the famous Keith McCree, author of the most widely used "Action Spectra of Photosynthesis", and also his Quantum Flux Density, Quantum Yield Curve, etc. The article is a good read for people getting starting with concepts like PPFD. In the article Keith uses the term PAR, but he means PPFD (a term he helped coin and was later adopted).

 

[mean mr.mustard]

I do it because I'm scared of the dark, I figure the plants are too.

Why can't I get them to bud?

 

[spurr]

I was PMing with Rumpleforskin and he and I both agree that for gardens with lower light levels (low irradiance), below what is ideal for cannabis, longer daylengths (ex. 24/0) can be beneficial. That is why for little lights, like CFLs, 250watt HID, etc., using longer daylengths can make plants grow faster; i.e. it's about DLI.

My main point throughout this whole thread is that for best growth rates, cannabis should be given very bright light (high irradiance), and have a dark period. Some growers who use little lights may not be able to provide sufficient light intensity (irradiance), so they could benefit from 24/0. However, that does not mean they are doing what is ideal for their plants, they are simply 'making due' with what they have.

To provide the fastest rate of growth, and most healthy plants, using high irradiance and a dark period is the way to go (that allows for the same, or higher DLI with a night period as the DLI found without a night period under lower irradiance). That has been proven true via. controlled scientific experiments countless times on many C3 plants like cannabis. And it has also been found true by those of us who grow cannabis at high irradiance with a dark period, vs. high irradiance without a dark period.

 

[bobman]

In this paper it concludes 1500 ppfd but it mentions no DLI

http://cat.inist.fr/?aModele=afficheN&cpsidt=21075598

 

[bobman]

Do you have any idea, ballpark figure, what a 1000 watt hps will run., in terms of ppfd and DHI

 

[VerdantGreen]

@ all,

I made a typo in the post where I uploaded the following paper, the Lux exceeded 12,000; not 120,000...ooops!

"Photosynthesis and Cannabinoid Content of Temperate and Tropical Populations of Cannabis sativa"
F.A. BAZZAZ, D. DUSEK, D.S. SEIGLER and A.W. HANEY
Biochemical Systematics and Ecology 1975, Vol. 3, pp. 15-18

hey spurr i was reading the paper and the conclusion cites it as 120,000 lux too (which is defined (by wiki ) as 'brightest sunlight' -

related question, if i were to by a lux lightmeter to measure lux canopy etc, would i be better to buy one that went up to 50,000 or 100,000 or 200,000 ?
would love to by a ppfd one but i doubt i can afford it and i cant even find one sold in the UK!

thanks

VG

 

[spurr]

In this paper it concludes 1500 ppfd but it mentions no DLI

http://cat.inist.fr/?aModele=afficheN&cpsidt=21075598

Yup, I uploaded that paper in full text already. All four studies I have found that looked at PPFD found ~1,500 to be ideal. And for Lux, the one study I could fine, and I uploaded, found 12,000 (and possibly higher) to provide highest net rate of photosynthesis.

 

[bobman]

So how does 1500 fit into your model and why is there no mention of DLI. With your model that puts DHL over 60 for a 12 hour period.