Light Burn? - Cannabis Infirmary - International Cannagraphic Magazine Forums

10-20-2005, 06:17 PM

I've searched and looked at multiple sick plant threads but I don't know if I see something that looks like this.

This happened on 2 out of 7 of my plants two days ago. The only thing I've done to the setup was a 50% lucas mix 2 days prior to this burn and lower the light a little because the temps were nice and low. I don't think that the nutes are the problem.

Is this light burn? They were even worse this morning. Crinkly and feel like paper. It's weird because it's not the whole plant, just the middle set of branches. It's not getting any worse except for the leaves already effected.

Any ideas?

toofat · 10-20-2005, 06:34 PM

How close do you have the lights? Place your hand over the plant for a few seconds, if it is too hot for your hand then it is too hot for your plants.

10-20-2005, 06:53 PM

You know I did use that method. The light was at about 12" and temps were low 70s, so I thought I could drop it down. Dropped it maybe 3" - the next morning they were burnt. I have an air cooled light and can get my hand within a few inches before I really start to feel the heat. This happened at about 17 days old, PH at 6.5

Verite · 10-20-2005, 07:15 PM

Looks like radiant heat burn from the lights to me. I get the same thing when they get too close. A spot here or there in weird enough places to rule out a feeding problem.

10-21-2005, 01:40 AM

Yeah nute burn usually starts on the tips and edges and there would be a bit more yellowing to go with the crispness. What wattage is the lamp? How much air does your fan move? I've heard of peeps saying they could kiss their 1000s glass (I don't suggest trying this) when exhausted properly.

GreatLakes THC · 10-21-2005, 02:59 AM

Sounds like you have a heat burn, but I'd also look at your pH. 6.5 is high for most hydro setups. That may be the cause for the leaf curl on a few of your other leaves in the 2nd picture.

GreatLakes THC

10-21-2005, 04:43 AM

yea i think it was heat burn also but keep this in mind also it happend to me when you water make sure not to get it on the plant i can bun the leaves the water acts like a magnifying glass when the light hits it and evan thoe you light is no way to close it still can burn well just an idea good luck

**guineapig** · 10-21-2005, 05:03 AM

man i hate light burn....weedwrapperman is right on about nute burn starting at the edges and working inward.....if you see tiny burnt out spots like these in the center of leaves it is most likely due to a hot-spot.....especially if you noticed them after lowering your light.....i have seen this happen even when plants were placed below a light-mover.....could've swore it was nute burn but it was light burn....who would've thought plants can still get burned even when placed below a light mover?

-kind regards, GP

10-21-2005, 02:07 PM

Thanks for the replys gentlemen. I think you all are right. The plants are still growing except for those set of leaves that were burned. I guess even though the temps were very cool, the plants were still too young for that powerful light. Btw it's a 400w halide.

I'll check PH tonight and see about lowering it a tad.

10-21-2005, 06:51 PM

Is it safe to snip these leaves off? They don't look like they are doing the plant any good at this point.

10-20-2005, 06:17 PM	#1
stretchpuppy Guest Posts: n/a	Light Burn? I've searched and looked at multiple sick plant threads but I don't know if I see something that looks like this. This happened on 2 out of 7 of my plants two days ago. The only thing I've done to the setup was a 50% lucas mix 2 days prior to this burn and lower the light a little because the temps were nice and low. I don't think that the nutes are the problem. Is this light burn? They were even worse this morning. Crinkly and feel like paper. It's weird because it's not the whole plant, just the middle set of branches. It's not getting any worse except for the leaves already effected. Any ideas?
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10-20-2005, 06:34 PM	#2
toofat Member Join Date: Jan 2004 Posts: 862	How close do you have the lights? Place your hand over the plant for a few seconds, if it is too hot for your hand then it is too hot for your plants. __________________ “Being happy doesn't mean everything is perfect. It means you have decided to see beyond the imperfections. " EVERYTHING I POST IS FOR ENTERTAINMENT PURPOSES ONLY. SO, I GUESS YOU COULD SAY THAT I AM A BIG LIAR.
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10-20-2005, 06:53 PM	#3
stretchpuppy Guest Posts: n/a	You know I did use that method. The light was at about 12" and temps were low 70s, so I thought I could drop it down. Dropped it maybe 3" - the next morning they were burnt. I have an air cooled light and can get my hand within a few inches before I really start to feel the heat. This happened at about 17 days old, PH at 6.5 Last edited by stretchpuppy; 10-20-2005 at 06:55 PM..
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10-20-2005, 07:15 PM	#4
Verite My little pony.. my little pony Join Date: Jul 2005 Posts: 4,750	Looks like radiant heat burn from the lights to me. I get the same thing when they get too close. A spot here or there in weird enough places to rule out a feeding problem. __________________ Strains by Verite .......................... Holy Grail Intro, Seeds at Seebay, Private Breeders Orange Diesel Intro, Seeds now at Seedbay
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10-21-2005, 01:40 AM	#5
Guest Guest Posts: n/a	Yeah nute burn usually starts on the tips and edges and there would be a bit more yellowing to go with the crispness. What wattage is the lamp? How much air does your fan move? I've heard of peeps saying they could kiss their 1000s glass (I don't suggest trying this) when exhausted properly.
	Quote

10-21-2005, 02:59 AM	#6
GreatLakes THC an Arthur P. Jacobs production Join Date: Mar 2004 Location: Where the Neons turn to Woods Posts: 3,219	Check your pH... Sounds like you have a heat burn, but I'd also look at your pH. 6.5 is high for most hydro setups. That may be the cause for the leaf curl on a few of your other leaves in the 2nd picture. GreatLakes THC
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10-21-2005, 04:43 AM	#7
Guest Guest Posts: n/a	yea i think it was heat burn also but keep this in mind also it happend to me when you water make sure not to get it on the plant i can bun the leaves the water acts like a magnifying glass when the light hits it and evan thoe you light is no way to close it still can burn well just an idea good luck
	Quote

10-21-2005, 05:03 AM	#8
guineapig Moderator Join Date: Aug 2005 Location: In spite of my rage I am still just a rodent in a cage Posts: 4,601	man i hate light burn....weedwrapperman is right on about nute burn starting at the edges and working inward.....if you see tiny burnt out spots like these in the center of leaves it is most likely due to a hot-spot.....especially if you noticed them after lowering your light.....i have seen this happen even when plants were placed below a light-mover.....could've swore it was nute burn but it was light burn....who would've thought plants can still get burned even when placed below a light mover? -kind regards, GP
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10-21-2005, 02:07 PM	#9
stretchpuppy Guest Posts: n/a	Thanks for the replys gentlemen. I think you all are right. The plants are still growing except for those set of leaves that were burned. I guess even though the temps were very cool, the plants were still too young for that powerful light. Btw it's a 400w halide. I'll check PH tonight and see about lowering it a tad.
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10-21-2005, 06:51 PM	#10
stretchpuppy Guest Posts: n/a	Is it safe to snip these leaves off? They don't look like they are doing the plant any good at this point.
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