Careful, you CAN give plants too much light

2 week from seed, got 2 sets of leafs and put my pups under a 250 mh. It was 20" and the canopy never got over 75.

Still on straight water, no nutes yet.

You could almost see the damaged chlorophyll, they got stunted and didn't like the light.

Back under 100 watts of 6500k CFL's and they are happy again.

What the hell? Guess I have a ways to go until MH vegging.

do you have pics?

that is one of the stupidest thing iv heard...sorry to say...but plant thrive for sunlight

lyndonm33 said:

that is one of the stupidest thing iv heard...sorry to say...but plant thrive for sunlight

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Go read the FAQ, and try again.


High Light - yes, it’s true, you can give our faves too much light. Cannabis does not receive full sun from sunrise to sunset in its natural state. It is shaded or given reduced light levels because of adjacent plant material, cloudy conditions, rain, debris and dust collection on the leaf surface, twilight periods of early morning and late afternoon, and light intensity changes caused by a change in the seasons. Too much light mainly serves to bleach out and destroy chlorophyll as opposed to causing leaf cupping, but it often goes hand-in-hand with high heat for indoor growers. Again, back off on the light and concentrate on developing/maintaining an efficient and robust root system. Keep in mind that all but equatorial material receive less light during flowering than during the vegetative stage.

i'll be back with more info on this subject..........

My 1 week old babies curled 18" under a 1000w mh bulb. It wasnt heat or humidity, i know it. I raised the light to 32" and the cupping lessened. I installed a 400hps at 18" and they uncupped. I reinstalled the 1000w mh at 32" and the cupping began after 3more days (on the new growth).

So, now i'm back to the 400W while I LST the crap outta 'em. I am fairly positive my lighting was causing this.

Anyhow, here's my post regarding it. https://www.rollitup.org/marijuana-plant-problems/276353-seedling-leaves-curling-up.html#post3510023

lyndonm33 said:

that is one of the stupidest thing iv heard...sorry to say...but plant thrive for sunlight

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Then you are just as stupid. Maybe not from a 250MH......but it happens, there is such a thing as too much lumen penatration.

a 250 watt MH will not give to much light, thats the most retarded thing I've heard.

Outside you get around 10k lumens per sq foot in direct sunlight

and a 250 watt mh is producing 22.5k lumens, how big is your area/how close is the light to the plant... but yeah you can't give to much light.

I dont believe too much light is possible. Maybe too close to the plants but at the proper distance from the canopy you cant have too much light. To the OP, try raising it up a foot or so and see how that works.

Mr Bomb said:

I dont believe too much light is possible. Maybe too close to the plants but at the proper distance from the canopy you cant have too much light. To the OP, try raising it up a foot or so and see how that works.

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OK I am going to clear up this internet misinformation. You ABSOLUTELY can have too much light. This occured in my plants with a 1000w hps at 8 inches from the plants. I grow with a water cooled fixture so heat is not a factor... Again, too much light is indeed possible. I moved the 1000w to 12 inches and the problem went away.

Mr Bomb said:

I dont believe too much light is possible. Maybe too close to the plants but at the proper distance from the canopy you cant have too much light. To the OP, try raising it up a foot or so and see how that works.

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I find it amazing how many folks actually believe this crap, that you can not have to much light

next to overwatering I would put too much light as one of the biggest mistakes new growers make

the sun is at 10K lumens at noon at the equator,,,,,,nowhere else !!!!!!!

Get a light meter folks, walk around with it, you will discover that it is more important/helpful than a ph meter (if your a soil grower, if in hydro then ph meter more important)

in pic one are buds I harvested in Jan grown under 97 watts (actual) was 47.2 grams dry 1 65 watt cfl and 1 T9 (see avatar)

pic 2 is an example of a perfect garden, notice how high the lights are, how green and relaxed the plants are, how even the canopy is and how consistant the bud growth is

250 watts is NOT too much light.. and to think it is is just stupid. I went from seed to flower with 400 watt hps and they were just fine.. This grow I even added an additional 150 watts of cfl..

riddleme said:

I find it amazing how many folks actually believe this crap, that you can not have to much light

next to overwatering I would put too much light as one of the biggest mistakes new growers make

the sun is at 10K lumens at noon at the equator,,,,,,nowhere else !!!!!!!

Get a light meter folks, walk around with it, you will discover that it is more important/helpful than a ph meter (if your a soil grower, if in hydro then ph meter more important)

in pic one are buds I harvested in Jan grown under 97 watts (actual) was 47.2 grams dry 1 65 watt cfl and 1 T9 (see avatar)

pic 2 is an example of a perfect garden, notice how high the lights are, how green and relaxed the plants are, how even the canopy is and how consistant the bud growth is

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dude, you can grow with less light but that doesnt look like 47 grams to me.. granted you do have a nice set up, and i think thats the only way possible to grow with such a small amount of lighting, with tons of refletion... and of course you can grow with tons of Hid lights even if they are high up if you have enough light .... u are very wrong my friend.. Im sure it is possible to have too much light, but 250 watts is NOT too much... You are being silly..

this is my first grow.. with a 400 watt from seed.. 2 plants over 110 grams dry.. harvested in Jan.

YES YES YES You can have to much light. I put that on ur mom. Anyways, durring flowering, lower the lights and youl get more THC production. To close, youll loose bud weight. There is a happy medium. All sorts of things make this a challanging discussion. I will always be the chicken or the egg subject. Im out. SS

sagensour said:

YES YES YES You can have to much light. I put that on ur mom. Anyways, durring flowering, lower the lights and youl get more THC production. To close, youll loose bud weight. There is a happy medium. All sorts of things make this a challanging discussion. I will always be the chicken or the egg subject. Im out. SS

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way to not read anything and just post...

Not sure it is to much light. Might have been to fast. when I use the 400w mh I start at week 2 or 3 and move the under them light over about a week. a few hours a day and keep adding time every day. Just like moving outside. Just the way I do it I've never suffered from to much light. Most of the time wish I had more.

JN811 said:

dude, you can grow with less light but thats not that much weed u got there.. and of course you can grow with tons of Hid lights even if they are high up if you have enough light .... u are very wrong my friend.. Im sure it is possible to have too much light, but 250 watts is NOT too much... You are being silly..

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I did not come here to argue

I did not mention a 250 watt light

I think I'm in Newbie Central where New growers come to learn?

The OP is trying to tell them there is such a thing as too much light, I posted to support that as I feel it is important to spread the truth about growing to the newbies

47 grams with 97 watts of light off of 1 21 inch tall plant is 1/2 gram a watt dude and that oz and 1/2 will last me 3 months, till the next harvest, it's all the weed I need, may not be a lot to you, but my needs are simple

Your plant yield looks good what was the wieght? plant itself could have done a lot better from what I see in your pics IMO, not a bash

yes you can definitely have too much light. i had my 600w MH vegging some bag seed. i had it about 18" from the top of my plants and they were very small when i put them under. i can keep it very cool in there. if i want i can have it 65 but i keep it around 82. they were stunted and just unhealthy. i moved my light about 3 feet up to get some stretching and after a day their health has improved and their growth rate for sure has. my grow cab is 2x4x6

JN811 said:

way to not read anything and just post...

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wwwaaaahhhhhhhhhhh!