Why go 24 hours lights on??

[smokefrogg]

i have yet to try vegging for less than 24 hours, everything i read tells me it's a waste of time and you'll just end up waiting longer the plants to get as big, i recall jorge cervantes mentions this in his medical marijuana growers book

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lol, controversy arises whenever GOD is brought up. then you get someone sheepishly calling another a sheep when in fact they/we are all sheep to one degree or another really when it comes down to it

thank god for cannabis, and the sun to help power it, and for sleepy time when it goes down....thankful the cannabis plants don't seem to require it like we do, who knows though, maybe they do grow more but start to go wacky and hallucinate such as we do without sleep? hmmm...

 

[spurr]

I have yet to try vegging for less than 24 hours, everything i read tells me it's a waste of time and you'll just end up waiting longer the plants to get as big, i recall jorge cervantes mentions this in his medical marijuana growers book

Please do not assume Jorge Cervantes is correct, he is not, on many topics. In terms of lights on 24/7 he is wrong and he can provide no scientific proof showing he is correct.

I called him out by PM a while ago about the vast amount of wrong info he wrote in his books using assumptions and hearsay on his part. Like how he suggests 1,500 ppm for Co2, but that's too high and hinders plants, incl. cannabis. And like his claims that plants don't use green light well for photosynthesis, which is false.

Plants grow the most during the night and very early morning hours. I can provide references...

 

[spurr]

"night" time doesn't need to be 100% dark; take the moon light nights for example. I can explain why in terms of irradiance and spectra and time of irradiance, but in simple terms: very low light (without any red or far-red light) is pretty much the same as 100% darkness for plants in terms of their 'nighttime'.

 

[Japanfreakier]

My plants are kind of dumb and don't read a lot of research papers, but they grow the quickest under 24/7, too bad they can't tell us why.

 

[spurr]

japan,

Read my post about DLI on page two for important info about sum of light over a day, it's not about the hours per day, it's about the photons per day.

Your plants don't grow the most in 24/7 of light given the same DLI in 18/6 as 24/7, etc., no C3 plants do that I am aware of. You need to use analytical measurement methods to know when plants grow the most, just looking at them doesn't tell us much worthwhile info. That is a major flaw in most cannabis claims (i.e. myths), they aren't formed using analytical methods of quantification and production of scientific theory (which isn't the same thing as "theory" to a layperson).

I could explain further why plants do not do as well under 24/7, but I already explained it well enough I think.

That said, if you're happy with using 24/7 I'm happy for ya

 

[Japanfreakier]

Dude all I need to know is that I get more weight with plants vegged under 24/7. I don't need to read research papers on it, just measure the weight.

 

[spurr]

Hey

The problem with using weight is that it's a rather poor and indirect method to judge success of light regimen (or other environmental variables). Weight is affected by a vast myriad of factors*, so we can't say 24/0, or 20/4, or 18/6 means more yield (other than anecdotally) unless we account for other major factors that affect yield.

FWIW, using weight as a method to judge an environmental variable without accounting for other important factors is a logical fallacy called "post hoc ergo propter hoc"**, Latin for "after this, therefore because of this". Most info on cannabis comes from that logical fallacy, esp. info in most cannabis books. That is not to say using that fallacy will produce an incorrect outcome, the problem is it's not provable.

We should use DLI (Daily Light Integral)*** instead hours of light per day because 24/0 with a new lamp/ballast means greater DLI than 24/0 with old lamp/ballast. That means two grows, one with new and one with old lamps/ballasts will provide different amounts of light per day, and thus provide different rates growth due to different rates of photo-reactions (e.g. photosynthesis, Co2 fixation, etc.). It's the amount of light (photons) per day (DLI) that matters, not the hours of light per day in terms of 24/0, 20/4, 18/6, 17/7, 16/8, etc.

To continue with that example: if using the new lamp/ballast we can run a shorter day and provide the same light per day as the older lamp/ballast. Both lamps/ballasts will provide the same growth assuming the SPD's (Spectral Power Distribution) will be the same, which isn't true assumption; the old lamp will have a different SPD than the new lamp****.

So when a grower tests a 24/0 light regimen and a 18/6 light regime, and finds 24/0 yields more, a grower can't assume the increase in hours of light is what increased the yield, or at least not alone.

Each grow with the same light regimen (ex. 24/0) is different in DLI, VPD, SPD, bud moisture content, etc.. That means using weight as the way to find the best light regimen isn't ideal. That also means a long light regimen that works well for grower A might not work well for grower B.


* examples:

1. moisture content of buds when weighed. Greater moisture contently means more weight but not more bud. That is why factoring out water weight by accounting for moisture content and coming up with 'dry weight' of buds is needed in analytical analysis. For example, most buds have a moisture content of < 35%, so we should factor out the 35% to find weight of the bud without any water. This is easy to due with a few grams of bud if if it's a good average representative sample of the harvest. As little of 10 grams should be used for bigger harvests, but a person could use 1 gram if they wanted to.

That means a grower can't accurately compare two grows if the grower doesn't use 'dry weight' of both grows. This is also why two growers comparing and competing yields do know the true winner unless both growers report 'dry wight' of buds.

2. Co2 levels

3. PPFD (Photosynthetic Photon Flux Density; or Lux, or lumens); this is a separate, but directly related issue to DLI

4. Air to Leaf Vapor Pressure Deficit (VPD; calculated using RH, canopy temp and (ideally) average leaf temp)

5. Nutrients

6. Media-water status, media moisture content (by wet weight gravimetric basis) and media water tension; for growers not using aero or NFT

7. Media properties such as air porosity, water-holding capacity, total porosity and bulk density; for growers not using aero or NFT.
​

** "The Post Hoc fallacy derives its name from the Latin phrase "Post hoc, ergo propter hoc." This has been traditionally interpreted as "After this, therefore because of this." This fallacy is committed when it is concluded that one event causes another simply because the proposed cause occurred before the proposed effect. More formally, the fallacy involves concluding that A causes or caused B because A occurs before B and there is not sufficient evidence to actually warrant such a claim." ref.


*** DLI is the sum of light per day. It can be used with Lux, or lumens, or preferably PPFD.


**** The SPD and irradiance degradation of lamps over time is one reason there is no accurate conversion from Lux to PPFD with lamps. The other reason being Lux and lumens are weighted for human eye sensitive colors and PPFD is not weighted at all. Weighted means giving more value to wavelength X than wavelength Y due to how the subject (ex. human retinas) are affected by wavelengths (ex. in the visible range for human retinas). Using a spectroradiometer can help make conversion from Lux to PPFD a lot more accurate for a couple of important reasons due to reflector, ballast, lamp age, etc.

 

[Japanfreakier]

I think I'll just use the weight because that's all I care about.

 

[SumDumGuy]

Why do i always see people who grow plants in veg with 24 hours lights on and no hours of dark?

anyone heard of the calvin cycle?

plants gotta sleep too, converting the molecules back to the starting constituents.

Thoughts, ideas, etc.. greatly welcomed.

Hi thcrefugee,
Putting aside our love and respect for these plants.. In veg they are to be treated as power-plants. I run my plants like factories. No sleep ever in veg. The only darkness they see in veg should come by way of an accidental power outage.

I've run 18/6 - 20/4 - 24/0 and the latter brings the best overall result on structure. Doing this you can constantly play with EC levels and increase accordingly. My plants are currently no taller then 7" and I am slowly working towards the 8th internode on day 31. Mind you I burned them and they needed time to recover but your plants WORK for you and NEED to be treated as such in veg!

By leaving lights on 24/7 you guarantee closer internodal spacing. Plants stretch in the dark and I do not like stretch. Aside from the EXPLOSION in growth my reason for the 24/0 is to achieve much smaller spacing while increasing overall structure in a shorter amount of time.

INDOORS YOU ARE GOD!

EDIT:
It makes me sad to see so many growers neglect side branching or just blaming the strain as a non bushy strain. You can ULTIMATELY control all this by leaving your lights on 24/0 and pinching the top as she grows. Then once the side branches reach the top - PINCH ALL THE TOPS TOGETHER! EVEN MORE SIDE BRANCHING FROM THE SIDE BRANCHES! This is yet another benefit of 24/0 as you're using the effective power of the light to heal your plant as she grows along.

 

[Forest20]

OK this is off topic but cannabis can be grown in 12/12 lighting as well...

 

[spurr]

I think I'll just use the weight because that's all I care about.

We can't use weight for anything but a very anecdotal outcome, nothing we can hand our hats upon. I wrote the 'whys' above. We can't use weight for anything but anecdotal evidence unless it's by 'dry weight' (without any moisture) and after accounting for other factors that affect yield more than hours per day.

We need to use DLI, even if it's only Lux-DLI (vs. PPFD-DLI) when comparing daylengths. Plants don't use 'the hours of light per day' for photosynthesis, they use the photons per day for photosynthesis...in other words:

The plant couldn't cares less about how long the day is (not in terms of flowering), however, the does plant care about the total photons per day, i.e. PPFD-DLI (and incidence photons too; i.e. PPFD).
​

 

[arcticsun]

if you go 24h lights on, you dont have to light isolate your veg chamber, it doesnt matter if there is a slight light leak etc.. its just easier

 

[Japanfreakier]

We can't use weight for anything but a very anecdotal outcome

People like you can link studies all day long, doesn't change that I get more bud from 24/7 than I do from 18/6, I understand that you would prefer to talk nonsense about studies and so on, but I go by weight. Put down the studies and just try it for yourself, don't let the studies convince you reality isn't reality.

 

[WaterFarmFan]

I am a proponent of 24/0 as well. However, I like several weeks of 18/6 before flowering to transition to 12/12. If you veg 24/0 under a 1K MH, you will see the benefits...

WFF

 

[spurr]

People like you can link studies all day long, doesn't change that I get more bud from 24/7 than I do from 18/6, I understand that you would prefer to talk nonsense about studies and so on, but I go by weight. Put down the studies and just try it for yourself, don't let the studies convince you reality isn't reality.

I think maybe you do not understand why yield can't be used as you want to use it for anything by wholly anecdotal evidence. And you ignored everything I wrote to you. That's too bad because what I wrote is new info to most cannabis growers; using what I wrote, people can become better growers with better yield...

I have anecdotally tested 24/0, 20/4 and 18/6 and 17/7 and 16/8, just like you. But the HOURS per day doesn't matter, it's the PHOTONS per day that matters. The time (in veg) when hours of light per day matters is when the night is non-existent or too short, then the plant suffer vs. having a night time.

What it sounds like to me, is you maybe do not provide enough irradiance, so you need to provide the lower irradiance for a longer time period (hours) to provide high DLI for better growth. You might want to try increasing your irradiance and reducing your day hours...I bet you would be surprised at the result in better growth and health, with the same, or probably better yield..

If you provided the same DLI to two gardens: one with a night of 4-8 hours, and one with no night, the garden with night would be heather, grow better and possibly yield more (it certainly won't yield less). These are facts of plant physiology...you can't claim otherwise with any degree of correctness.
​

/spurr bowing out

 

[Japanfreakier]

I think maybe you do not understand why yield can't be used

I'm a grower, only thing I care about is the weight. End of story. get over it. I'm not going to read your boring links because I already know I get more with 24/7. What don't you get about that? Not rocket science.

 

[CANNATOPIA]

what about in flower?!

 

[Fear]

LOL damn he told you.

 

[Hammerhead]

When I first start I use 24/0 then after a few weeks and change to 20/4 I leave it here until im ready to flower 12/12. This works very well for me.

 

[The Phoenix]

We have taken a good long look at this subject because it's our business. When we are running 1kw bulbs for veg, we see no appreciable benefits overall for going 24/0. The extra cost of running each 1kw bulb an extra 42 hours per week per bulb did not show enough benefits to justify the extra cost. In a typical 4-8 week veg senario, thats 168-336 kw hours savings per bulb, and that really adds up when you are well over baseline rate. Burning 1 1kw bulb 24/0 at a typical SoCal home (with everything else in a typical home and no A/C) will have your electric bill at over $200 a month, and with multiple bulbs the over baseline rates go even higher.

We've looked at the plants very carefully and notice that at certain times of the day with artificial lighting, the plants did not have their perkyness when running 24/0.

It's really noticable when running outdoors. We have been vegging plants many years with a combination of indoor and outdoor lighting, and it's there were you really notice the plants benefiting from a dark cycle. After a day in the sun, when the sun is setting, the plant leaves start to droop down, and we bring them inside for a 6 hour dark period before giving them supplimental lighting. After that dark period, the plants are standing at attention and ready to go again.

You can run them any way you want, but the price to performance ratio says go with the electricity savings, and give the plants a 6 hour rest when running the big bulbs, unless you have the money to burn and dont care.