Browning of sugar leaves- Nute burn/ light burn?

Have had some nute burn on this one plant almost from the beginning. Have 3 other plants all grown same without the problem… Watered today, day 61 on this OG kush auto grown in FFOF at 850 ppm. Just noticed this when done. Browning of sugar leaves near top of plant. Have been running 2 spider farmer sf2000 in a 4 x 4. Have been keeping the lights at the close end of their specs. 12". Raised them to 15" but considering a flush tomorrow. Buds are putting on weight and dense would hate to lose this plant at this point. Think this is light burn or do I have a nute problem. Any help appreciated. A lot of resin in the areas that seem to be burnt the worst if that makes any difference.

I have been looking and can’t find any leaf problem pics that look like this. Hoping someone out there has seen this or has some idea what it might be.

Maybe a calcium deficiency?

Thanks for taking the time to respond. Had a calcium deficiency at start of grow and determined the fact that I am using rainwater with a ppm of 20 was the problem. Have been using Calmag with every water since and the problem went away. This looks different than that to me.

most likely not light burn. Light/heat burn would impact the bud as well. What is water pH?

@pp3121 Thanks for the reply. I did a soil slurry test on this plant before I watered yesterday and ph was 6.6 and ppm was 610. The last time I watered to runoff was 8 days ago and the runoff ph was 5.8. So I watered yesterday at ph 6.9. The runoff on this plant yesterday tested out at 6.3 so am getting it back up. When I watered 8 days ago I fed fox farms tiger bloom at 1200 ppm. I had always had yellowing of a lot of leaf tips, just the tips, on this plant and after that feeding saw a little more yellowing along a few of the serated edges but not a lot so I backed off to 850 on this one plant when I watered yesterday. I have another OG Kush growing right next to it that has been getting the same treatment with no problems. I have already checked them this morning and no noticeable change but only been 12 hours. This may be stupid but have read not to foliar feed ( which I haven’t) when the lights are going to be on the leaves as the droplets can act like magnifying glasses and burn the leaves. Since most of the burning is where there is a lot of resin on the leaves could this do the same thing and focus the light. Still considering a flush if it looks gets any worse. I did raise the light to 18" last nite after I posted which is the high end of the spec for my lights during flowering. Any more input greatly appreciated.

Is the discoloration on the top or also on the bottom leaves?

If you have corrected your pH, the damaged leaves will not be repaired. Keep a look on the newest growth for the best information. As you eliminate suspects, that can help narrow down the issue. I’m still thinking it’s not the lights.

Looks more like a phosphorus issue, but I can’t be sure.

I would like to get some more experienced people on board.

@Covertgrower @Hellraiser @dbrn32 Hello. Could you please give a little insight into possible culprits for this issue? Appreciate your time. Trying to keep learning.

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12" is probably too close for the light. It’s capable of running there, but would have to be plants that aren’t light sensitive and hardend off properly. If you get some deficiencies or burning of leaves the damaged leaves will be even more susceptible to further damage.


If it’s only happening to leaves in the upper canopy then most likely a light related problem. I’d keep it at 18".


I think you got solid advice from the others.

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Thanks for all the help. Been out this morning and don’t think it’s any worse. Regarding what @PP3121 said about light burn would affect bud as well, I do have 2 or 3 of the calyx in the midst of the burnt leaves that look a little brown at the tips, right at the top of the plant. Am not ruling out the calcium deficiency, have been giving minimum dose of cal mag in rainwater that is 25 ppm and maybe not enough, and ph has been a little low which may be locking it out. Am going to go ahead and flush this plant at next watering as I can tell I am pushing it a little hard with Tiger Bloom and leave the lights at 18". Will post pics of top and bottom of leaves but would say the damage just appears to be on top. Sorry about quality of pics, small leaves and couldn’t get closeup to come out very good. Thanks again for all the help.
leaftop leafbot

Sounds like some good advice there form some very knowledgeable growers.

@dbrn32 @Hellraiser @Covertgrower I’m wondering if the tips of the serrated leaves near the tops…see how the tips look as if they are slightly turned upwards, and seem to almost have little white dots… is an indication of light/heat stress? As I said, love to keep learning.

Thanks for helping out.

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@dbrn32 @Hellraiser @Covertgrower @PP3121 Yes thank you all for taking the time. Will update this thread with progress on this, maybe help someone out down the road with same problem.


Do you have an overall shot? Support ticket? I’ll need more information.

Hey @Covertgrower , There is a shot of the whole plant at the beginning of the thread and I haven’t done a support ticket. I just checked on the girls and problem seems to have stopped progressing. Like I said, will leave the light at 18 and just do a plain water trying to bump up pH a little and think this plant will make it through ok. This is only my second grow so all help appreciated. Haven’t posted much as I can usually find what I need in old posts just couldn’t find anything like this. I am beginning to realize genetics has a lot to do with growing. 4 plants all grown the same and quite a difference in how they behave. Thanks again for the help. I read a lot of new postings and would like to help others but don’t really have enough experience to do much good, so appreciate all the experienced people who take the time to help us newbies. If something changes will get back on here a provide more info.

Thanks. I was just trying to learn a little in terms of differentiating nute burn and light burn stress signs. So, I was looking at @pogo pics and noticed the top serrated leaves and how the tips on each serration were slightly bending upwards with an apparently white dot look. I understand nute burn would be more plant wide whereas light burn would be concentrated more towards the tops.

Appreciate the time and info.

What’s it towards bottom or the top?
Usually those leaves that yellow and whitish spots are nutrient burn, and ph or a combination. More photos would give more information.
Always happy help.

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No problem at all, we all experienced growers started somewhere. We all had our first grows once, and some of us before the internet. I enjoy following along with everyone’s grow style too.


Will update soon. Fortunate to begin growing with the technology to allow this type of interaction for sure!

Said I would keep this updated so maybe someone down the road will know what to do or not to do. Today was water day and after inspecting this plant think yellow leaf tips and yellowing edges is getting a little worse so am going to flush this plant. The last time I watered I did a soil slurry test and pH was 6.6. I watered with pH 6.7 and fed Tiger bloom at 830 ppm. Runoff tested at pH 6.3. Still suspect a possible calcium deficiency as pH was running lower prior to this and have been edging it up as I think calcium likes a pH closer to 7 for good uptake. This plant is in a 10 gal. fabric pot. I ended up running 8 gallons of water thru it… I did use CalMag at 5 ml/gal and a half Tbsp per gallon of molasses per gallon along with 10 ml/gal of fox Farms Sledgehammer flush.
Adjusted pH to 7.4.
At the end of this runoff tested at pH 6.3. My runoff numbers always come out lower than soil slurry test so hopefully next watering day soil slurry test will come out in the high 6’s. Still keeping the light at 18". Today is day 65 on the OG Kush auto. Last grow I had one OG and I chopped it at day 100 so still got a way to go. Got some nice buds going on it that are pretty dense and getting bigger so hope this one hangs in there.

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