How much light is too much.........?

HOW much light is too much and how much light can a plant handle...HEAT IS NOT A ISSUE....FORGET ABOUT HEAT...lets focuss on power of the light.
ALSO how do plants and new growth adapt to light...?

While many say "you cant have enough light", I beg to differ. Although it is improbable that you would experience too much light on small operations, it is possible. One sign would be that the leaves will start to bleach. I cant give you an exact number as to what would be too much, but I doubt you would spend that much money to get too much light to begin with. It should not be a major concern.

Yea, ya can have too much light. I have noticed it. The plants will turn yellow. I have seen it where a leaf on top of a leaf had left a imprint on it. yellow and green stripe.

if you want a really powerful bulb get the new HPS/MH hybrids by Hortilux. Awesome light spectrum!!!

yes i too whould like too know this...i have two 400watts hps in my 2x2x4 cab only one is on and the plants look a lil yellow..thought it was nutes but thats not it..but all in all the plants look good and seem to love the light..

I've heard you can't? however, i've seen the plants turn yellow as well..I was thinking this was something else???

well ive been studying all day for my agronomy final, and from our book it states that if light is not the limiting factor in photosynthesis then CO2 will be, so if you add CO2 to your grow room then that would help out your grow (caron dioxide compensation point).

Don't know what'd you'd use to measure it but a .10 percent CO2 level is supposed to double the photosynthetic rate of some crops (normal is .03).

hope that helps, hah

If you look here and use their formula for lux to lumen conversion you can compare full sunlight lumens and don't exceed that.

Sorry, I'm too lazy to do the math for you.

http://en.wikipedia.org/wiki/Lux

have u seen the new duel light setup where u can use 2-1000 watt in one reflector. I think that's maxing your lighting

I promise you, if you are looking for the best light out there there is no match to these.
http://www.eyehortilux.com/superblue.html
Hortilux's newest invention. If you refer to the chart posed by OregonMeds you will see the relationship between lumes and lux. These bulbs produce lux that is comparative to direct sunlight on a bright day. Anything else does even come close. Not to mention they give off a pretty awesome blue and yellow light simultaneously. Kinda psychedelic if you take a few puffs first.

In theory, you can't have too much light. The problem is that the light spectrum of any bulb will contain a lot o infra-red (IR), which causes a rise in heat that you can't really lower through ventilation.

Matter can be heated by using a heat source, where heat is transmitted through convection (carried by faster moving air particles) or by an IR source. IR produces heat inside the plants leaf, by stimulating the electrons of your plants molecules. IR does not produce the same amount of convection, but your leaves can still burn up because of it.

So the problem is not really too much light, it's too much IR due to your bulbs spectrum. Sadly, I have never heard of a lamp that does not produce IR. And the higher your bulbs wattage and the more light it produces, the higher the IR expulsion is. That's why people relate light with heat, they being relatively proportionate (if ignoring external variations).

I also believe that 'diminishing returns' should be a consideration. I'm sure it would differ widely between different genetics, but there is always a point where you'll add more and more light and not see more and more improvement. This is probably far below the point that even radiant heat through a glass pane, or actual bleaching would occur, IMO.

how much light is too much? - when the plants are screaming OUCH! and the leaves are getting crispy... this is usually because you have the light too close to the plant though..

there seems to be a "rule of thumb" of having 50watts/sq ft of HID lighting... i think this is too low... the more light you give it the more yield you get up to a point...

I use a screen that is 2.5' x 7' and put it under 2KW... that is 114W/sq ft and the plants love it... the trichomes are formed to block the light from hitting the surface of the leaf in its later stages of life... the more light it sees, the more trichs it makes on the surface, which act as little umbrellas to sheild the plant from the light that is hitting it at any angle... this is probably a form of adaptation to high light areas... the trichomes actually take all the light and refocus it to the bottom of the trich head where it is magnified many times and focused on the disc cell which produces THC... or so I hear.

i like the broad spectrum bulbs, with the addition of the UV spectrum for best results... but if you can deal with the HEAT, pay no mind to that 50w/sq ft rule.

Infra red light is by definition "infra" or "below" red. Which just means light that has a wavelength we can't see. WE can't see it, then therefore we can not measure it. Just like we can not see wind, yet we measure it by the force it applies. Same with infrared light we measure by it's thermal effect. Because that is how we discovered infrared light. A thermometer reacted to infrared light, and someone was intuitive enough to decifir the cause of said effect. As far as ignoring external variations go, DON'T. But this is all to much for info for this question. Here is what you need to know.

A photon is a particle of light. Photons come in different colors. Photons are the true food of your plant. Your plant makes electrons (electricity) from these photons (like a solar panel does) and uses that to literally split water molecules and along with CO2 create carbohydrates(sugar).

Blue Photons = powers chlorophyll production, powers cell actively, energies the stomata movement and makes the plant follow light.
Green / Yellow Photons = not much action from these bands of light.
Red Photons = makes sugar from CO2, powers chloroplast production, signals light and dark times among other functions.
Strong blue and red light photons are also needed for good carbon dioxide uptake.

I hope this will shed some LIGHT on your problem. (Pun intended)

on a clear day in direct sumlight the sun is about10,000 lumens psf at high noon.

5-7000 lumens psf much more and its a waste of electricity

MEANGREEN69 said:

yes i too whould like too know this...i have two 400watts hps in my 2x2x4 cab only one is on and the plants look a lil yellow..thought it was nutes but thats not it..but all in all the plants look good and seem to love the light..

Click to expand...

1 400 watt light goes nicely in a 3x3 room so 2 in a 2x2 room is way a lot. you can use a 150 in a 2x2

BloodShot420 said:

how much light is too much? - when the plants are screaming OUCH! and the leaves are getting crispy... this is usually because you have the light too close to the plant though..

there seems to be a "rule of thumb" of having 50watts/sq ft of HID lighting... i think this is too low... the more light you give it the more yield you get up to a point...

I use a screen that is 2.5' x 7' and put it under 2KW... that is 114W/sq ft and the plants love it... the trichomes are formed to block the light from hitting the surface of the leaf in its later stages of life... the more light it sees, the more trichs it makes on the surface, which act as little umbrellas to sheild the plant from the light that is hitting it at any angle... this is probably a form of adaptation to high light areas... the trichomes actually take all the light and refocus it to the bottom of the trich head where it is magnified many times and focused on the disc cell which produces THC... or so I hear.

i like the broad spectrum bulbs, with the addition of the UV spectrum for best results... but if you can deal with the HEAT, pay no mind to that 50w/sq ft rule.

Click to expand...

light is mesured in lumens not watts you could do a 2.5x6 with 2 400watters hell of a lot cheeper to run 800 than 2k


srry for the tripple post really really high

i could do 800 watts in there, and i have, but i UPGRADED to 1Ks...

lumen wise...

400w 55,000 lumens
430w 58.5k
600w 87k
1000w 145k

Or...

400w-- 137.5 lumens per watt
430w-- 136.0
600w-- 145
1000w- 145

so, i could use 110,000 lumens with 2x 400w bulbs on my 17.5 sq ft screen... to get 6285 lumens/sq ft...

or, use the 1Ks, get 6% more efficiency, get 290,000 lumens, or 16,571 lumens/sq ft.. 60% brighter than high noon... yeah, its unnatural, but they love it.

with these numbers, its easy to see why people measure HID light in watts... its roughly linear but the 600s and 1Ks are most efficient... i wasnt happy at all with the performance of the 400w lights...

BloodShot420 said:

i could do 800 watts in there, and i have, but i UPGRADED to 1Ks...

lumen wise...

400w 55,000 lumens
430w 58.5k
600w 87k
1000w 145k

Or...

400w-- 137.5 lumens per watt
430w-- 136.0
600w-- 145
1000w- 145

so, i could use 110,000 lumens with 2x 400w bulbs on my 17.5 sq ft screen... to get 6285 lumens/sq ft...

or, use the 1Ks, get 6% more efficiency, get 290,000 lumens, or 16,571 lumens/sq ft.. 60% brighter than high noon... yeah, its unnatural, but they love it.

with these numbers, its easy to see why people measure HID light in watts... its roughly linear but the 600s and 1Ks are most efficient... i wasnt happy at all with the performance of the 400w lights...

Click to expand...

must be the extre penatration your goin for????? i use a 400 watt and lst in a 3.5x3 room and am verry happy

if it works for ya than great, i think iwould just keep an even canopy and spend less on my electric bill, it would be like 30 bucks a month for 800 watts here and like 75 to run the 2k but if its workin for ya than happy growin

with my electric plan (higher base rate, fixed $0.03/kw hr)

800 would cost me $12.96 to run 18hrs/day for 30 days...

2kw is $32.40 for 30 days of veg... and $21 a month for flower... its really nothing when you think about it - if i bought a 1/4 oz on the street it would cost more than a whole cycle with 2KW... and it would be nowhere near the quality