Is there such thing as "To much Light?

[Kushy]

So this is not a huge problem just wanted somer input on the matter.

What has happened is I have a 1000W HPS that is aircooled in a 2x4x7 sunhut and I had it dropped down to maybe 36 inch from my plants. I noticed that they started to form a taco shape on the tops of the plants which from what I know from recent grows that, that is a sign of over heating. But as my thermometer in the room is right at the top of my tallest plant and is reading 78 degrees F.

So from what I know I wouldn't think you could have to much light. But has any one had this problem or any one know anything about it.?

 

[808kahumai]

too much heat, not enough humidity, not enough air flow...maybe, for starters. You need a fan and a mist spray bottle. Of course with out pictures, it is hard to tell. What are you feeding them? How old are the plants? Are they in veg or flower? What is the humidity? What are you growing them in? I could guess, but that kind of info would be helpful. Cheers!

 

[Hundred Gram Oz]

Here take a look at these diagrams, they are a good help





HGO

 

[RockyMountainHi]

Hey HGO, is that figguring an open hood, or air-cooled with glass?

Just checking.

 

[Kushy]

I have An air cooled hood with air getting vented out. I usually leave the door open with a fan oscilating back and forth and an extra fan bringing in fresh air from outside. Humidity ranges from 30-50. I do mist the plants when ever I can. The plants are about 2 weeks into veg. Strains are Northern lights, Bubble gum, big bud and mazar from http://www.marijuana-seeds.nl/ from the seed specials. Im growing them in Royal Gold a coco based saol. Using RO water with organic humboldt nutrients. But thanks that chart really helps. Rep up to Hundred gram.

 

[Mo. G]

it could be stagnet heat. how many ocilating fans do you have.

 

[mexilandrace]

yes there is such a thing as too much light, plants can even get sunburned

 

[magiccannabus]

That chart is WRONG! Its based on a formula the creator obviously had no understanding of. That is not actual lumen measurements, or at least not with the bulb inside of a reflector and a room with reflective walls.

That chart says my HPS is 1/4 (25%) as bright when the light is 2x as far away, thats just not true.

I know this one is not with a HID light, but it shows that that inverse-square law DOESNT apply when your not using a point source of light.

This chart shows only about a 50% decrease in light with twice the distance, and near the sides the amount of light actually INCREASES with distance. Please destroy that chart...

All that being said, my 400w HPS is 2-4 in away from the tops and they look great. I don't think too much light can cause the damage your describing. His chart says your 1000w can be 10 inches away and be in the 'optimum' zone.

It is called the "law" of inverse squared for a reason. It's a basic principal of all science and thermodynamics. If all energy didn't follow this law, our universe would be unhinged. Larger bulbs still radiate, and that radiation still tapers at a distance. In truth, even an LED is not a true "point source". You calculate the size of the emitter, and apply the inverse square law to it, and you can see exactly how it will radiate, all with math, without even turning it on. Our very existence as we know it requires this law to be absolute.

Your light IS 1/4 the intensity at 2x the distance, that's a fact of science you can't avoid. You can only minimize it by capturing that stray light and reflecting it, thus your light is actually more saturated along the walls.

A 400W HPS so close to the canopy isn't necessarily going to hurt them, but you could be wasting light. You also may experience that the plants directly under it behave differently than those receiving this light at such a shallow angle. Intensity is good, but good levels of dispersion are useful too. Otherwise you may need to move plants around to keep things happy. I think you might experience better coverage if you raised that light a bit. Then again, if it's working for you, that's awesome.

 

[Kushy]

I have one oscilating fan on the floor pointing up into the bottom of the plants. Its a small sun hut. 2x4. I also have an outside fan pushing fresh air in from outside. Maybe my plants actually love the light and trying to reach for it. Any way good points by everyone. I didnt think it would get thisa much attention.

 

[D.I.trY]

yeah the inverse square law is BOLLOCKS! It assumes a bulb suspended in space with zero reflection. Think of a spot beam at a theatre for example. All the light is reflected in one direction and there is zero evidence of an inverse square law! Everyone who quotes the inverse square law as fact of physics hasn't done much independent thought on the subject!

Back to topic, maybe there is not too much light (although im SURE its possible) but too much of the wrong kind of light. InfraRed is light also! - its too often muddled with heat, but air temperature and IR are really very different. IR has a negative impact on plant growth and its emmission increases when the bulb gets really hot. So u should get the bulbs as cool as possible. IR light is just slightly longer wavelength than far red in the visible spectrum. Perhaps its a good assumption that warm coloured bulbs, eg hps and warm cfls actually produce more IR.

 

[bongoie]

i thought and read the more light or lumens the better ? with that said i run a 600 W {digital ballast that the manufactures rates at 105 th lumens } roughly 6 inch from a air cooled reflector . i get results but lower popcorn has more frost that top bud . now i'm not sure if i am doing the right thing thanks for an interesting thread .

 

[dbfr3sh]

Well I would raise the light if I could, its a 400w in under 4 sq/ft and I dont have much height. I don't have the tools to test it but I am sure the light isn't 1/4 strong with 2x the distance. In my steup there is no place for the light to spread out to and the only surface absorbing large percentages of photons are my plants..

That law is pretty simple, you only have a certain number of photons and if allowed to go in ALL directions the density of them will decrease.

Seriously though, the reflector BARELY fits in the cabinet so no light is wasted upwards. All the walls are painted white and I have white panda film on top of the containers. The light cannot keep spreading out indefinetly, and therefore makes that law pointless.

sweet...but your still wrong. at one foot away you have full lumens, if you add another foot you get 1/4 the total lumens. doesnt matter if you have a super duper setup, its a fact and your still wrong. ask google mayb there wrong too

 

[dbfr3sh]

i thought and read the more light or lumens the better ? with that said i run a 600 W {digital ballast that the manufactures rates at 105 th lumens } roughly 6 inch from a air cooled reflector . i get results but lower popcorn has more frost that top bud . now i'm not sure if i am doing the right thing thanks for an interesting thread .

maybe because of radiant heat?

 

[Fluke]

very interesting thread indeed. And I too have noticed that since I moved my 600 away from the tops slightly(just on a hunch) The tops ar frosting up quite nicely. This could also just be natural. We'd really have to see a comparative grow.

 

[bongoie]

maybe because of radiant heat?

temps are good at plant height . use a 12 inch circulating fan in room and a 6 inch directed at the cool tube
. not sure thanks for ur input , it's appreciated . my plants are close to the source

 

[D.I.trY]

sweet...but your still wrong. at one foot away you have full lumens, if you add another foot you get 1/4 the total lumens. doesnt matter if you have a super duper setup, its a fact and your still wrong. ask google mayb there wrong too

No sorry, but i think you are wrong. Did you read my post -how do you explain a spot beam?

 

[charles_bronson]

the amount of light plants absorb and the measure of lumens dont really correlate. also, with a bulb close, you lose a lot of flavor, the buds right under it suffer and dont smoke as nice as the ones not right under the bulb (aircooled cooltube or not)
so i dont think i could argue the inverse square law but i don't think its what you should base your lamp height at. there are just too many other factors that law fails to include (flavor of bud, health of the plant, desirability of product, overall yield, smaller footprint, darkness in the corners, etc.)

just my experience over the years, it may vary for others but i keep a 600w air cooled cooltube about 18 inches away from the plants in flowering with great results. next run with air cooled sun systems reflectors should be better for footprint though

 

[D.I.trY]

oh yeah for sure you would get very misleading temperature readings depending on shade etc. Lets imagine you could remove all IR wavelength and just have just photosynthetic light hitting ur babies your thermometer is still gonna heat up from the light hitting it but not as much as it would with the IR included. I am thinking right now that if we deliver too much IR (wrong spectrum light) to the leaves than is normal under daylight environment that plants have evolved in, then it really damages the plants - AND i'm thinking this is STILL true if you cool surrounding air and measure perfect temperatures with your thermometer. Its kinda like sun burn with with IR not UV - but i cant find shit on google about this. I really wish i could find out more about this.

 

[Kushy]

Hey thank all of you for replying to my thread. I really didnt think it was huge deal. But I see now that it is a great deal to my plants. I had my 1000w hps 5 feet away from my plants for about a week and just yesterday I put it about 2 feet away. It is a noticable difference in lumens from what my light reader is showing. The top of my 7 foot sun hut has minimal light up top because the light is at the bbottom, but is still has light. The closer the better but I think there should be an equal medium.

 

[Kushy]

So i took my light tester not knowing how it works but it shows on a scale from 0-2000. 6 inch's from the light it was ranging around 2000. At the top of my plants wich would be 36 inch's from the light it was ranging around 700. It is a crappy meter but it works fine and I hope this helps a little