Is this light burn?

[Kystro]

Anybody?

 

[Olderfart]

Looks to me that you have something going on, but maybe not light burn. I will be interested in comments from more experienced growers.

You might get more responses by filling out the the infirmary form to describe the grow.

 

[Kystro]

Looks to me that you have something going on, but maybe not light burn. I will be interested in comments from more experienced growers.

You might get more responses by filling out the the infirmary form to describe the grow.

It's baffled me as it was going strong for 3 weeks straight. I thought either light burn or nutrient burn but I don't think it's the latter as in previous experience nutrient burn starts from the bottom working up... Could it be humidity fluctuations as when lights out it rises to 85%! 50 rest

 

[Arthur]

What kind of light? And how far off the canopy? Twisted new growth makes low calcium levels my knee jerk reaction, but not seeing other signs.
Temps?

 

[Olderfart]

It's baffled me as it was going strong for 3 weeks straight. I thought either light burn or nutrient burn but I don't think it's the latter as in previous experience nutrient burn starts from the bottom working up... Could it be humidity fluctuations as when lights out it rises to 85%! 50 rest

I would like to help, but I would just be guessing. I see no obvious sign of excess light though, and I would think that if light were the issue, your fans would show more sign of it - praying, canoeing, upcurled serrations. I see none of that.

85% is definitely a bit high, but at this point in the cycle, I am not sure how that could cause what you see. Humidity that high might reduce transpiration enough to cause nute mischief though, so the humidity is a potential issue. @Waira may be able to help, and @Mañ'O'Green may yet chime in since your recent photo.

You will certainly need to keep RH lower during flowering, or you risk bud rot.

Good luck with it, I hope that you get more help from the more experienced crew on here.

 

[Kystro]

What kind of light? And how far off the canopy? Twisted new growth makes low calcium levels my knee jerk reaction, but not seeing other signs.
Temps?

It's a hps and it's 28" from the top of the plant. So maybe it's not light burn? So you're leaning towards calcium?

 

[Olderfart]

Calcium is carried to the growing shoots via transpiration - more transpiration, more delivery. This was the reason for my comment on the 85% humidity. If the high humidity lowered transpiration enough, it could bugger up calcium delivery, and perhaps other nutes, even if there is enough in your medium.

 

[Arthur]

It's a hps and it's 28" from the top of the plant. So maybe it's not light burn? So you're leaning towards calcium?

Hps, do you have a digital thermometer like this? Guessing your leaf temps are way up...Was wondering hps... with hps, temps are much more rigid than led, it gives off a ton of infra red that warms things... a rockin' hps grow will max out at about 75* or 24C. In veg these plants love high rH, so your humidity doesn't bother me much. What's your temps? After looking at the picks more, looks more wilted than twisted


Edit: I shoot for a leaf temp of 78 to 82 degrees. That's led or hps. With led leaf temp is maybe 2* above ambient. Hps can be 6 to 10* higher.

 

[Kystro]

Hps, do you have a digital thermometer like this? View attachment 1240534Guessing your leaf temps are way up...Was wondering hps... with hps, temps are much more rigid than led, it gives off a ton of infra red that warms things... a rockin' hps grow will max out at about 75* or 24C. In veg these plants love high rH, so your humidity doesn't bother me much. What's your temps?

24.5 usually mate

 

[Kystro]

Calcium is carried to the growing shoots via transpiration - more transpiration, more delivery. This was the reason for my comment on the 85% humidity. If the high humidity lowered transpiration enough, it could bugger up calcium delivery, and perhaps other nutes, even if there is enough in your medium.

Thanks mate