Light Intensity

[GreatLife4All]

With the addition of the new digital ballasts with configurable light intensities... I was just curious if anyone had played around with lowering the intensity of the light during late bloom, early ripening stage.

It would seem that by doing this you are more closely modeling an outdoor grow (I am willing to admit this may not be a goal). In the fall, both the color of the light shifts (from blue to red), and the intensity of the light falls off (we are farther from the sun and the light passes through more of the atmosphere).

With the old magnetic ballasts, one would have had to swap out the bulb and the ballast both. But today, you can simply flip a switch and get the same effect.

So, has anyone played around with actually lowering the intensity of light during the late stages of flowering? And if so, did it have any effect?

 

[Glockdoc]

ive asked the same question only to get a smart ass remark. i asked what if i had veg'd under 1k and then flowered with 400 do you think i could hit gpw on the 400's intensity with prior 1000w veg.. just like outdoors; which yields laugh at any wattage indoor grow. the person told me " thats like saying u can get 1000 miles to the gallon if u push your car"! i aint down for starting cyber fights so i didnt reply....just felt like saying "still got that 1000 miles to that 1 gallon" but that would of just followed with insults and such...u know..
that was months ago...but it turns out...thats my scenario at the moment..flowering under a 400w i have 3 sour blueberry that where vegged under 2 1000's side by side...so we will see. bud sites are just showing so i will make sure to keep u posted.

just for some insight thou one person did say why would u lessen your max yield on the gpw.. use a 1000, grow like shit, but still yield more then a 400 simply because of watts..u know?

 

[Voltrom]

Many of us are still trying to figure out what's beneficial to emulate from the outside. Some say blast that bitch with hps all the way. Some say dual spectrum whole grow, some people move their lights to simulate the "decrease in light" that you we're talking about later in the years.

I honestly believe if you veg with a 1k then flower with a 400w that you'll get great results. Perhaps not as much as a 1000w but who knows. You might wanna run some lumen figures in your head to actually see if a 400w downgrade would be just like outdoors. The plants would respond..

I for one believe the vegetative state is where the real growing occurs.

If you have the same strain under your belt and you know what to expect compare those results with the 400watter flowered bud. Even if you lose a zip from your average yield id believe that you stumbled onto a way to save 600w of energy.

Do post your findings brother.

 

[Glockdoc]

just harvest yesterday, 400g wet weight. got 2 main colas that a little smaller then a 40oz bottle. the third got a semi-topping and was stunned for a bit and didnt yield as well but the undergrowth did well and even better it survived! unfortunately i dont have any cuts taken of this strain; but nonetheless cant say the "myth" at hand is still neither confirmed or denied.

 

[Icemud]

Great question. I have never found a solid scientific study or anything relating to "proof" that a lower intensity of light during the last 2 weeks makes a difference or not, BUT, I was told by one of my friends and a very very experienced Norcal grower/farmer that you get more weight if you raise your lights up the last 2 weeks of flowering/ dim the output... I have tried this and so far been pleased with the results, but I never did a side by side comparison to see if it actually made a difference over just giving them full intensity until harvest. Overall I take his advice because he grows some amazing bud and I have to respect his experience, however, I still have not found a solid yes or no answer if it makes a difference. Wish I had more of an answer for you, but wanted to share what I have learned.

 

[Glockdoc]

Great question. I have never found a solid scientific study or anything relating to "proof" that a lower intensity of light during the last 2 weeks makes a difference or not, BUT, I was told by one of my friends and a very very experienced Norcal grower/farmer that you get more weight if you raise your lights up the last 2 weeks of flowering/ dim the output... I have tried this and so far been pleased with the results, but I never did a side by side comparison to see if it actually made a difference over just giving them full intensity until harvest. Overall I take his advice because he grows some amazing bud and I have to respect his experience, however, I still have not found a solid yes or no answer if it makes a difference. Wish I had more of an answer for you, but wanted to share what I have learned.

sorry its been awhile since u posted this; but i believe that what your buddy and do should hold true!
its almost as the buds (like seedlings) are stretching for the intensity that was once there
i had made sure my three sour blueberrys were as close to light as possible, started seeing some heat issues, so lowered my plants.
that maybe the reason why the colas were huge... that and the 1k veg most likely

 

[ecofrog]

you get more weight if you raise your lights up the last 2 weeks of flowering/ dim the output... I have tried this and so far been pleased with the results,

Under a HPS, I push my plants off to the side the last 5 days so they get low direct light but still bright enough to bioprocess. Yellow, green and blues are more penetrating than reds so in theory, it makes sense you can 'raise' your lights.

 

[NCDude]

good post

 

[Radogast]

The range of solar radiation winter to summer is 75,000-100,000 lumens at extreme places like Iceland.
For most of the world the variation is closer to 90,000-100,000.
That is less than the variation between 400w(50,000) and 1000w(100,000).
Rough numbers but you get the idea.

As with the sun, your DISTANCE variation of +- 10% on a 1000w HPS is closest to the summer/winter variation.
Winter = one inch farther away from the lights. Less variation than many colas

 

[Srilania]

I don't know if doing what you're asking would be wise. But, if you wound up say, realizing you're blasting too much light, that ability to dial it down will make your setup a lot more flexible. I'd keep it wound up high, unless a need from light bleaching or heat causes you to need to drop the intensity just a bit.

 

[oldhippie64]

I don't have any answers just wanted to point out a observation of mine. the earth orbits in a oval (actually it ike a spirograph drawing).it reaches it's closes point around the winter sotice. That is while our north pole is turning away from the sun the earth on a whole is moving closer to the sun. I think that woud have to be taken into account too and really compicates things in figuring out a program to run lights.

 

[Cannabelle]

As far as light intensity goes, I would think that plant genetics should be considered.

For instance, Russian ruderalis genetics could care less about light intensity and duration as long as its leaves receive enough light to manufacture the energy it needs for it's growth cycle.

In tropical regions, like Hawaii, cannabis/pakalolo genetics would need to dial into rainfall patterns, ethylene abundance of ripening tropical fruits and birds in order to go into flower as light and temperature remains fairly constant year round. Birds indicates insect control, seed dispersal and guano fertilizer. The locals in Hawaii must contend with a lot of law enforcement helicopter activity and theft. Locals prefer small, yet potent, guerrilla grows rather than quantity grows. Bigger yielding plants are likely to get spotted by helicopter or stolen by neighbors.

Light intensity and duration should be balanced with strain genetics, available growing space, available growing medium, available nutrients, water supply and even the abundance of gases produced by decaying organics and ripening fruit. Currently, much of cannabis production remains in the domain of horticulture hobbyists rather than agriculture professionals. Once cannabis becomes an acceptable agriculture commodity, agriculture scientists will be conducting studies on how to save time and money producing cannabis on a large scale using less water and light or idiot proofing strains to actually enjoy mass marketed Miracle Grow products.

 

[eebwen]

I'm growing an Northern Lights autoflower under cfl's. During the day I put her in the window to increase the lumens she gets which quadruples because of the suns intensity compared to the cfl's. Can anyone tell me if this is alright to do to the plant or will I have problems with her?

 

[eighty9concen]

I run light dep green houses as well as indoor and full term outdoor plants. The light deps that are harvested in july/august, produce a way better product than plants that were let to go full term in greenhouse/full sun and finish in october. Almost indoor in quality, actually better than a lot of indoor i have seen around. That leads me to believe that more intense light makes for a better product. I run 1000w de's indoors full blast all way to the end and get amazing results and great yields. Imo and experience, the stronger light in july/august produces a way better product than september/october light. Which also leads me to believe that 1000w all the way to the end will give a better harvest.

Not trying to offend any one in any way, its just my personal opinion and experience that using anything lower than 1000w to flower with is going to lower your final quality/yield

 

[Terp Monster]

At the end of flowering, intense light typically comes with intense heat. That heat becomes very significant under HIDs and to a lesser extent close LEDs.

That excess heat tends to cook off the lighter (lower boiling point) terpenes and to a lesser extent cannabinoids. Conserving more of the lighter terpenes helps deliver the wonderful taste/smell of well-grown cannabis. A cooler environment with lower air temps and higher lamps do the trick.