Is it heat or lumens that stress the plant?

Im considering getting a water chiller to allow the hoods to touch the girls but am unable to find a direct answer concerning if too many lumens is an issue. Many things I seem to read contradict one another when researching this manner. So what is it? Heat is a obvious stressor but can there be TOO many lumens directed on the girls? Why and whats your reasoning?


Thanks
Manifest

yes there can be too much light, think about chlorosis

What light are you using? I had an open hood 400 HPS and the heat was stunting my plants a little at 2 ft above the canopy. Then I got my cooltube and it's only 3 inches above the tops and they are fine. In my opinion, as Long as your plants are a month old and you don't defoliate, you should be fine!

The sun averages 7k lumens, most plants have adapted to be able to handle the sun. Over 10k or about 110,000lux if your a weirdo will bleach your plants. That's the sun at its strongest...when this bleaching occurs the plant is not being able to keep up chlorophyll production at rates necessary

Heat burns the plant in a different way, similar to having too much wind. From moisture being drawn out the leaves (transpiring)faster than the plant can replenish

I don't have a Cool tube I have a vented glass bottom hood with a 400 HPS.

I get a very nice light footprint from my larger rectangular shaped hood.

with my fans I can touch my glass with my hand and it is only warm.

I did see burning on my plant with my light at 10-12" high but at 16" I get no Burning.
I am sure I could go down to 14", to be sure I ordered a light meter.
One more way to work with a known vs an unknown.


Obviously mine has more surface area than a cool tube.

if compared with all the same variables which would be cooler an enclosed vented hood or vented cool tube?

just Curious??

A cylindrical cool tube will always cool and let air flow, better than the more expensive square counterpart that provides better light distribution..I have a 600 watt cool tube I can keep 8inches on the top of my sativas

Well i've seen ppl run cooltubes 1kw just inches away from plants since it was vertical.. uumm,, no problems with heat or "light bleaching"., the strain was indica hybrid~
temps kept steady at 75f~ hum @t 40%~

#cheer$

qwizoking said:

A cylindrical cool tube will always cool and let air flow, better than the more expensive square counterpart that provides better light distribution..I have a 600 watt cool tube I can keep 8inches on the top of my sativas

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I can get my 600 watt hps within 8" with my square reflector. The problem is the leaves will bleach that close to the light.
I have to keep it at least 12" away, not for heat reasons.

Cooltubes are a waste of money. They cool as well as my square reflector but do not distribute light as well.
I have a cool tube collecting dust.

qwizoking said:

A cylindrical cool tube will always cool and let air flow, better than the more expensive square counterpart that provides better light distribution..I have a 600 watt cool tube I can keep 8inches on the top of my sativas

Click to expand...

One grower I service has 12 bigfoot hoods all 600's, his plants are only an inch or two from the glass. He also implements light diffusers with each bulb. You should be able to get within inches if your set up is working correctly. Personally I don't believe you can have too many lumens in a grow room, it just has to be positioned correctly. JAS

Where is the asshole of the world? Just wondering..

Wherever I 'am!......lol

Ooooh I thought you meant like.. people say Louisiana is the armpit of the united states lol it is stinky there

Both. See my Plant Moisture Stress sticky in Plant Problems.

JonnyAppleSeed420 said:

One grower I service has 12 bigfoot hoods all 600's, his plants are only an inch or two from the glass. He also implements light diffusers with each bulb. You should be able to get within inches if your set up is working correctly. Personally I don't believe you can have too many lumens in a grow room, it just has to be positioned correctly. JAS

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"One grower you service", eh? Aint gonna touch that one.

No way, not with a typical horizontal hood. That is botanically impossible due to the destruction (bleaching) of chlorophyll/chloroplasts.

The crap I read so often in these forums: "you can't give a plant too much light" is just that, crap. When some one says that I know immediately they are a chest beating, attention ho newb who knows nothing about botany....what makes a plant tick.

Here are actual f.c. measurements I made years ago of 2 HPS in small, highly reflective hoods.....and no, I don't wanna hear any uppity crap regarding PAR.

DISTANCE FROM LIGHT............F.C. READING

.......................250W HPS...........600W HPS

Within 6" (Way off 10K f.c. scale, for both lamps)

6".......................10,000................10K+

8".......................7,100.................10K+

12"......................4,800.................8,700

18"......................2,800.................5,600

24"......................2,000.................4,200

30"......................1,400.................3,300

Frame of reference: sun = 9,000 - 10,000 average, clear summer day, high noon
Cool White fluor measured 2" from bulb = 1,200 f.c.

Enjoy,
Uncle Ben

qwizoking said:

Where is the asshole of the world? Just wondering..

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That would be CANADA, this guy is SIR GANGA hiding because he keeps getting made to look stupid. And we all know if canada was that cool, it would be a state!!!

intensity 1/ intensity 2 = (Distance 2 / distance 1)^2

My clone plant closest to the 400 watt hps bulb, within a few inches, is growing better than the one at 6 inches. Past the 10'000 of the sun but no bleaching or stress. Might be because this plant evolved at higher altitudes where sunlight is more intense. Not everything from a horticulture book applies to cannabis although most does.

yes yes and yes. and no no and no. you for got to add any information . are you using ac to cool the entire room to a nice cool 65 f for hydro. do you have a water chiller. ? what size lighting do you use ? what type of lighting ? how many kelvins ? air cooled ? or like my set up topless woman fanning it ? tell us some important info before asking .

1blazeking said:

My clone plant closest to the 400 watt hps bulb, within a few inches, is growing better than the one at 6 inches. Past the 10'000 of the sun but no bleaching or stress. Might be because this plant evolved at higher altitudes where sunlight is more intense. Not everything from a horticulture book applies to cannabis although most does.

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Not an attack, but sometimes negative results take time to poke their head out. I had a vert 400 watt hps about 6-8 inches from my ladies for the first 5 weeks of 12-12 and the entire veg phase... temps were kept the same throughout but eventually my leaves bleached out. Same with nutes. It was my first grow and went with AN anf followed the package instructions. At first it was fine but eventually got nute burn and leaf drop.

Just my experience

1blazeking said:

My clone plant closest to the 400 watt hps bulb, within a few inches, is growing better than the one at 6 inches. Past the 10'000 of the sun but no bleaching or stress. Might be because this plant evolved at higher altitudes where sunlight is more intense. Not everything from a horticulture book applies to cannabis although most does.

Click to expand...

Yes, this is the real world and it's called experience and botany. I'd like to see a photo of that plant using flash or natural light.