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Light Bleaching 101

L

LJB

This is textbook light bleaching.

v63s41.jpg


The same condition as what I posted in #10, which was grabbed from google images. I wonder if that plant wasn't in a vertical room.

Anyways, this happened to the tops on two of my plants - you can see the grow thread here.

http://www.icmag.com/ic/showthread.php?p=3000146&posted=1#post3000146

The temperature at the canopy has remained within the same range, 77 - 81, the only thing that has changed is the distance. After I moved it up to 12" from center, the leaves stopped curling upward and changing to this light green from a lack of chlorophyll.

The knowledge base is obviously a work in progress.
 
Does everyone concur?...that this is light bleaching?..(I've never done/seen that before...:bashhead:...)

Besides, moving them further from the light: any other suggestions?


That looks more like windburn to me. Light bleaching is more of a subtle yellow color that is evenly distributed at the top of the plant. Do you have fans that blow really close to your plants?

is this what you all are talking about?

01.jpg


Strange that it's on the lower part of the plant in this example.
That looks like an Iron def in early flowering.
 

Pinball Wizard

The wand chooses the wizard
Veteran
That looks more like windburn to me. Light bleaching is more of a subtle yellow color that is evenly distributed at the top of the plant. Do you have fans that blow really close to your plants?

very small fan, blowing on LOW...but, it is a small confined closet...blowing between canopy and bulb


never over 80 degrees...I watch my temps very, very closely

Today, I switched to a Hortilux HPS bulb...the bleaching has consumed the other plant, yet the buds look unfazed by what's happening to the fan leaves?
 

CalcioErba2004

CalErba
Veteran
I 2nd Hoss

It's windburn. I have always had problems with windburn myself. Even if a fan is on low, if it is blowing directly on the plants it will burn the leaves. The smaller the fan the more direct the air is coming through it so even on low it could be coming out faster than needed. It is best to use large area oscillating fans that don't always blow on the plants or in the same spot. What I did in my veg closet because I have the same problems is turn my fan to face a wall so that the air bounces off the wall first and doesn't blow directly on them. Increasing the distance between the fan and the plants also works. Hope this helps! Keep it danK! :joint:
 

Pinball Wizard

The wand chooses the wizard
Veteran
Today, I switched to HPS ... ...and moved the fan away

The 30% or less humidity probably didn't help anything either?
 

jyme

Member
pinball you never said how close you had the light from start. it could be light bleaching. you said they did start out white like light bleaching. i have notest that difernt strains can take more of one thing and less of another.it also could be windburn is the most efected area nearest the fan.if so its more plausable if not its less likely.
 

Pinball Wizard

The wand chooses the wizard
Veteran
It was about 12-14 inches away. I am beginning to suspect my reflector is fucked. It's a smooth curved polished aluminum reflector...I need to get a dimpled one....

actually the plant, farthest from the fan...started turning white on the leaves; a week and a half ahead of the other plant?...and it was mostly the middle leaves?

very confusing...maybe?...too much UVb?..(CMH bulb)
 

jyme

Member
ive seen dimpled ones do some strage things. they break the focus up but some times the have hot spots in them causing bleaching in spots and other spots are fine.
 

jyme

Member
tell me.did you start them under the cmh or floros? and the more i think about it 12 to 14 inches away isnt to close. now that you changed every thing is it progresing or has it stoped?
 

Pinball Wizard

The wand chooses the wizard
Veteran
First three weeks vegging under fluorescent; switched to 400 CMH bulb at 4 weeks (12/12). Problem started showing on one plant after 2 weeks and the other plant at 3 weeks.

Moved the plants twice as far away. Switched to HPS lighting; because I thought too much UVb, MIGHT involved in the problem?
The colas seem unaffected and are growing slowly....:xmasnut:..(will post more pics at 5 weeks old)
 
My first post was a little bit in haste. It is classic leaf scorch. But I'm still confused as to whether it's caused by by too much heat or too many photons.

I've experienced what can be seen in photo in post 10, but only on flower directly under the bulb, not lower down. I've responded by moving the lamps up slightly.

same here, it happened only on ones directly under the lamp and only on top of head bud, along with some burn of the calyx and hairs on harder examples...

but the photo you are reffering to should be big temp difference between day and night...
 

hazy

Active member
Veteran
here you go. I just got done burning these babies, so you get a chance to see some nice fresh light burn. Moved them from under floros to under a 400. Put the light too close. You'll see a white leaflet in one pic. It was darkened and droopy the day before. I raised the light but not enough. I guess I just wasn't thinking. I don't like to get it closer than 14-15 inches. At least over 12. The second day it was about 12" away and it continued the burning. This is one day later.
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This one came out kind of weird with the spotting.
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swimmy

New member
Is this bleaching?

Is this bleaching?

I grew White Widow and it was tremendous. But it had white creamy stuff on the tip of top cola. Now I have Kush and it has the exact same thing. I don't think this is mold. We loved the White Widow. What is this stuff. Looks like a little pile of butter on the tops of some colas. Bleaching? Thanks for responding.
 

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