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Is this Heat Stress or Light burn?

Dipez

New Member
Hi, Took a look at my plants last night and saw that they had some signs of what I think is Light burn or heat stress. The temps are at a solid 75degrees though so I'm more leaning towards the light was too close and burning leaves. I'm surprised that the top leaves are fine though.

Ive got a 400wt MH bulb in there right now with a Yield master reflector with the glass in. The bottom of the glass is about 1-2" away from the very top of the plant. I normally keep the bulb about 6" away but I just switched to this reflector so I think this might be to close.

Any help is appreciated.

heres the pics

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ak481991

New Member
whats up dipez stop me if im wrong but wouldnt the top off the plant be affected worst and the damaged area off the plant is quite big but you would think it would only be in one area the leafs look dry tho a have never had a burned leaf or saw one so only going off what a can geuss sorry a cant help any more and best off luck on your grow
 

Dipez

New Member
whats up dipez stop me if im wrong but wouldnt the top off the plant be affected worst and the damaged area off the plant is quite big but you would think it would only be in one area the leafs look dry tho a have never had a burned leaf or saw one so only going off what a can geuss sorry a cant help any more and best off luck on your grow

Sorry but your post is hard to read/understand... Proper punctuation and grammar go a long way.
 

ak481991

New Member
you mean understand you can read it fine its in english not russian and proper punctuation and grammer go a long way in a english exam in my opinion
 

Hogdady

Plant of the Month: June 2010 - Nug of the Month: July 2010
Looks like light burn to me. Good test is to hold your hand at plant level with the back of your hand towards the light. You should be able to keep it there without any pain.
 

Dipez

New Member
Looks like light burn to me. Good test is to hold your hand at plant level with the back of your hand towards the light. You should be able to keep it there without any pain.

Yup I'm able to do that fine with no real heat being felt. I'm starting to think this happened before I changed over to a glassed reflector and the damage just started to show a little while after. Is that possible?
 

Dipez

New Member
Well I know i didn't miss it I rotate my plants every other day.. I guess it could be from the reflector being to close but I'm surprised the top isn't effected at all..

It doesn't look like chemical burn at all right? I don't think it does but just to be sure I'd like to get a second opinion. Also I'm not using nutes right now so I don't see how it could be chemical burn.
 

Goldengoose7

Plant of the Month: Sept 2011, Nov 2012 - Nug of the Month: Oct 2012
It does look a lot like light burn like what happens when a leaf touches a T5 or CFL bulb for several days. Only odd thing is that it is on lower leaves and not the top where this usually occurs. Are you using side fills?

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Goldengoose7

Plant of the Month: Sept 2011, Nov 2012 - Nug of the Month: Oct 2012
Not sure what you mean by side fills. If that means light on the sides no I'm not. I am using a 400wt MH bulb on the top of the plant. One thing to note is today its really hot outside and inside the grow closet I am getting 86 degrees right now. Normal days it is 75 though.

Yeah.. Sidefills as in lights pointing at the sides of the plant to help get light to the lower branches. I use them a lot (CFLs in clamp on shoplight fixtures) in my indoor grows rooms primarily during flower for the lower buds.

Based on those high temps it could be a heat stress reaction. 86 isn't deadly hot, but you are getting close. I would really try to prevent it from getting much hotter than that, espcially since your plant is showing signs of stress already.
 

Dipez

New Member
Yeah.. Sidefills as in lights pointing at the sides of the plant to help get light to the lower branches. I use them a lot (CFLs in clamp on shoplight fixtures) in my indoor grows rooms primarily during flower for the lower buds.

Based on those high temps it could be a heat stress reaction. 86 isn't deadly hot, but you are getting close. I would really try to prevent it from getting much hotter than that, espcially since your plant is showing signs of stress already.

Well theres not much more I can do for the temperature. I already have a 400cfm fan sucking air off the bulb and my reflector is glassed. Short of me getting an AC unit I don't know what to do.

I was considering putting a 6" intake fan sucking air into the closet but I have no clue how I would be able to do this without having light leak like crazy..
 

Goldengoose7

Plant of the Month: Sept 2011, Nov 2012 - Nug of the Month: Oct 2012
85 is within the acceptable range so don't worry too much, but your plant is showing signs of stress, so that is why I suggested trying to keep it from going too far above that.

Increasing your ventilation would help as would putting a fan on the plant directly on low to help keep it from heat stressing again.
 

Dipez

New Member
85 is within the acceptable range so don't worry too much, but your plant is showing signs of stress, so that is why I suggested trying to keep it from going too far above that.

Increasing your ventilation would help as would putting a fan on the plant directly on low to help keep it from heat stressing again.

I've actually already have 2 fans blowing on the plants from each side of the closet and 1 fan set on the floor pushing the cold air up.
 

Goldengoose7

Plant of the Month: Sept 2011, Nov 2012 - Nug of the Month: Oct 2012
Dipez said:
Hmm.. I don't have any PH test kits. I am actually looking to buy a PH tester right now. Not sure on what to get though. I've used the test strips for testing the soil PH when I was mixing it. If I remember correctly It was low 6s for water runoff, I could be wrong though.

I highly recommend the PH-200 by HM-DIGITAL/Hydrofarm. Great meter! I own two of them. One for my outdoor grows and one next to my Turbo Klone cloner. About $80.00 online and worth every penny. Went through several Hanna meters before I bought a PH-200. A far better and more accurate meter! It also has Auto-Calibration which is a BIG PLUS! :thumb:

I don't think your issue is pH in this case though. pH problems don't come on that quickly. They develop slowly over several days/weeks.

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