Is there really such a thing as "too much light"???

Ok so first off, yes i am highly medicated at the moment, and yes im sitting on the porcelain throne... So now that we got that out of the way, can you really have too much light in your grow tent? Like take my little veg tent for instance (2ftx2ftx5ft tall). If i managed to cram 12 vero29 cob's inside my tent with a total power draw of 800 watts and i was able to keep my tent at optimum temperatures, would it be too much light? Has anyone ever tried to find out how much light is too much? Could i just make a mini sun and cram that sukker in there haha?

How much God is too much God?

There is a such thing as too much light in the respect that with more light you need to upgrade your other parts of your system. The sun puts out 10,000 lumens per sq/ft on the earths surface so any calculation with respect to the correct par and intensity over that is not going to be used by the plant. With the upgrade in light you will need more airflow, heat dissipation, nutrients and water for the higher levels of transpiration and feeding. may need to supplement with CO2 to get optimum growth. The best thing is to get it in the range of 5000, to 8500 lumens per sq/ft. Get your nutrient schedule down, dissipate your heat well (nothing kills a plant like heat) keep your water levels correct in both hydro and soil.

The leaves start to contort and pull away from the light.

Dont learn this the hard way. Look at pro grows, all the 1k hids are 3-4 feet above the canopy.

I ran 800-1200W (dimmable digital ballasts) using 2 bulbs in a space less than 1m2, with the lights (air cooled) about 1ft above the canopy, very good results..... went for over kill as a one off experiment, i like to try stuff...

First off lumens is visible light to the human eye. And has nothing to do with plant growth. That's photons or par photosynthetically active radiation. The number of photons emitted.


Yes there is such thing as too much light.
Too much light will stunt growth, bleach plants, cause molybdenum deficiencies.




Also the sun produces 2000 umole/s at mid day at the surface of the ground. About 800 umole/s in the morning and afternoon. So about 1000- 1200 umole/s at the surface of the canopy is good.

Read up on all these.

Phytochrome / pfr, Emerson effect, inverse square law, shade avoidance.

Yes to much light is a real thing .
I just got a marshydro 300 .my grow closet is 2x2x 8'6 with my tong clone I have had to mount that light to the ceiling cause even at recommend for oem the plant was bleaching at three feet from the canopy .so yes to much is to much

Corvette kidd said:

Ok so first off, yes i am highly medicated at the moment, and yes im sitting on the porcelain throne... So now that we got that out of the way, can you really have too much light in your grow tent? Like take my little veg tent for instance (2ftx2ftx5ft tall). If i managed to cram 12 vero29 cob's inside my tent with a total power draw of 800 watts and i was able to keep my tent at optimum temperatures, would it be too much light? Has anyone ever tried to find out how much light is too much? Could i just make a mini sun and cram that sukker in there haha?

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Yes;



So from the chart you can quickly see two things; first, there's no point in ever going over 1500PPfd, and second that you get the vast majority of plant growth response at as little as half of that value.

In other words, no sense in blasting them; you run into diminishing returns fairly quickly and going overboard is definitely harmful.

Not to mention expensive; not only do you have to pay to generate all that light but even with COB LED you will still need to remove all that excess heat, another slightly more hidden tax on high intensity gardens.

Two or three sweet spots present themselves;

One is at about 450PPfd, where over half of growth is simulated with less than a third of maximum intensity. Not surprisingly, this is the realm of those seeking really high gpw numbers, but it isn't as space efficient for someone with a big monthly rent bill, leading to...

The second, at around 850PPfd, is going to give 75-90% of the best possible plant growth with just over half the intensity- and now we're talking some real big yield per square foot numbers without going crazy trying to keep things cool.

The third sweet spot is all the way up above 1250PPfd, and seeks to maximize returns per unit of space, power bills be damned! The only way this level makes any economic sense at all is if the value of the crop is high enough.

Yes, sunlight can and in hot, dry summer conditions often does exceed a plant's ability to absorb light effectively.

hyroot said:

First off lumens is visible light to the human eye. And has nothing to do with plant growth. That's photons or par photosynthetically active radiation. The number of photons emitted.


Yes there is such thing as too much light.
Too much light will stunt growth, bleach plants, cause molybdenum deficiencies.




Also the sun produces 2000 umole/s at mid day at the surface of the ground. About 800 umole/s in the morning and afternoon. So about 1000- 1200 umole/s at the surface of the canopy is good.

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The unfortunate problem with your answer is that most newbs have no idea what a umole is nor do they want to as it isnt required knowledge to grow great bud. I try to give an answer that they will understand and add in what they will need. Most people understand luminosity. They can read up on PAR (which is why I said with respect to PAR and intensity). Unless your becoming a scientist when you look up intensity of the sun as research material it will first tell you that its 10K lumens per sq ft on the surface. Once you research your lights you will find out where your PAR range should fall and then you can make an educated guess without going all poindexter on people.

herballuvmonkey said:

The unfortunate problem with your answer is that most newbs have no idea what a umole is nor do they want to as it isnt required knowledge to grow great bud. I try to give an answer that they will understand and add in what they will need. Most people understand luminosity. They can read up on PAR (which is why I said with respect to PAR and intensity). Unless your becoming a scientist when you look up intensity of the sun as research material it will first tell you that its 10K lumens per sq ft on the surface. Once you research your lights you will find out where your PAR range should fall and then you can make an educated guess without going all poindexter on people.

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+ rep
Keep it simple Simon

Overkill ftw

herballuvmonkey said:

The unfortunate problem with your answer is that most newbs have no idea what a umole is nor do they want to as it isnt required knowledge to grow great bud. I try to give an answer that they will understand and add in what they will need. Most people understand luminosity. They can read up on PAR (which is why I said with respect to PAR and intensity). Unless your becoming a scientist when you look up intensity of the sun as research material it will first tell you that its 10K lumens per sq ft on the surface. Once you research your lights you will find out where your PAR range should fall and then you can make an educated guess without going all poindexter on people.

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And the problem with your statement is that those of us who HAVE gone to the (very tiny) trouble of learning basic, important terms and concepts is that now you look parochial at best and plain misinformed at worst; you've conflated PAR and lumens, demonstrating that you don't have a solid grasp of any of these terms. So why should anything you say on the subject be taken seriously?

You're assuming noobs are too stupid to Google unfamiliar terms? Seriously?!

Stop giving advice that advocates for ignorance. It just makes you look stupid.

ttystikk said:

And the problem with your statement is that those of us who HAVE gone to the (very tiny) trouble of learning basic, important terms and concepts is that now you look parochial at best and plain misinformed at worst; you've conflated PAR and lumens, demonstrating that you don't have a solid grasp of any of these terms. So why should anything you say on the subject be taken seriously?

You're assuming noobs are too stupid to Google unfamiliar terms? Seriously?!

Stop giving advice that advocates for ignorance. It just makes you look stupid.

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Really bro. You just started learning this shit and now you are all high and mighty. Just Google par a d everything that comes up. Anyone can figure out what I was saying with common sense and Google

You have it backwards. Your statement is condescending and assumes people are dumb and need to be spoon fed while holding their hand with everything . Not giving people the benefit of the doubt they can figure it out for themselves.


Go attack someone esle. My statement was very accurate. I've explained this exact thing on this forum over a thousand times. So I'm not going to get in depth and so if someone doesn't understand it. They can either ask questions or research it themselves . It's that simple.

Anyone who wants to grow quality anything should learn the basics of everything in horticulture or not grow.

Even in that following post I stated terms to look up.

hyroot said:

Really bro. You just started learning this shit and now you are all high and mighty. Just Google par a d everything that comes up. Anyone can figure out what I was saying with common sense and Google

You have it backwards. Your statement is condescending and assumes people are dumb and need to be spoon fed while holding their hand with everything . Not giving people the benefit of the doubt they can figure it out for themselves.


Go attack someone esle. My statement was very accurate. I've explained this exact thing on this forum over a thousand times. So I'm not going to get in depth and so if someone doesn't understand it. They can either ask questions or research it themselves . It's that simple.

Anyone who wants to grow quality anything should learn the basics of everything in horticulture or not grow.

Even in that following post I stated terms to look up.

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I think you made a mistake. I was defending your position, not the ignorant one's.

Notice who my post was responding to.

ttystikk said:

I think you made a mistake. I was defending your position, not the ignorant one's.

Notice who my post was responding to.

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My bad I swear riu fucked up. I had an alert saying you quoted me and it landed right on the other quote. It didnt have his name. I should have taken a screen shot. Since it landed on that I misread it. I thought you were quoting me. I still need to wake up I guess or something

hyroot said:

My bad I swear riu fucked up. I had an alert saying you quoted me and it landed right on the other quote. It didnt have his name. I should have taken a screen shot. Since it landed on that I missed read it. I thought you were quoting me. I still need to wake up I guess or something

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No worries, bro. I get as frustrated with ignorance as it sounds like you do!

He wants simply bring simple,, YES you can have to much light,, duh

assuming you are using HID which most people are, 50w per square foot is a good mark to shoot for. 75w per square foot might be over saturation which is not good. This might change if you are for example using 50w per square foot of HPS and 25 w of MH or FS light, since they are on opposite ends of the spectrum. remember plants do not care about lumens. lumens are a measurment of visible light which is mainly green on the spectrum and is the only part of the visible spectrum they cannot photosynthesize. This is why the discussion of PAR and umol's/PPFD is so important. I am just trying to put it in terms that people can understand without spending all day on google reading about how to calculate their PPF. So 800w in a 4sq ft space is, um how should I say... overkill, try maybe a 150w hps or flourescent lights to avoid cooling.
really 4 square feet? did I read that right?