Leaves curling upwards

I’ve got a problem with my grow that I haven’t seen before. I know I have some yellowing tipping going on & am today reducing the ec level.

The leaves are turning up & some are going a bit brown & some are going a bit purple. I wouldn’t be surprised if the night temperature is at least partly the cause. Night time temps are probably down to about 64f. Lights on temps are 80-82F



They have been grown under 3500k Cree cobs & are getting fed at 1.1ec DTW.



My worst fear is bud rot developing. Does anyone have any ideas?



Thanks in advance

What's your PH sitting at? Curling tips- That's almost always a sign of incorrect PH! The brown ends are just over feeding but if it's not the whole leaf then you'll be fine. Again tho, I'm just telling you things you already know

Looking at your pics, you've got minimal damage. Those are some very slender leaves? Is it sat dom? Try a complete flush and re feed accordingly! Ps a little cal mag doesn't look like it'll go a miss either.

Where is your humidity at with lights on and lights off? Bud rot is usually a concern of high humidity and warm temp. I just resolved my high humidity by running a dehumidifier when lights are off.

Looks like light stress to me (toasty leaves curling upwards), are they too close the lights? I've seen the same symptoms in plants getting within 6 inches of LEDs.

I'd only worry about bud rot if your humidity is constantly over 65%

slinkysaurus said:

What's your PH sitting at? Curling tips- That's almost always a sign of incorrect PH! The brown ends are just over feeding but if it's not the whole leaf then you'll be fine. Again tho, I'm just telling you things you already know

Looking at your pics, you've got minimal damage. Those are some very slender leaves? Is it sat dom? Try a complete flush and re feed accordingly! Ps a little cal mag doesn't look like it'll go a miss either.

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Thanks for the help. I let the ph run from 5.6 upto 6.0 max & then set it back down. Yes it is a sativa dom strain. Funnily enough since posting this thread I've flushed thee 2 ladies & then given them a tad more calium & magnesium.
The main thing from my point of view is that it isn't rotting!

cheers

Trich-o-matic said:

Where is your humidity at with lights on and lights off? Bud rot is usually a concern of high humidity and warm temp. I just resolved my high humidity by running a dehumidifier when lights are off.

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Thanks for gettin gback to me. The huidity is 55% at the moment. It's normally around the 50-60 mark most of the time.

kushedy said:

Thanks for the help. I let the ph run from 5.6 upto 6.0 max & then set it back down. Yes it is a sativa dom strain. Funnily enough since posting this thread I've flushed thee 2 ladies & then given them a tad more calium & magnesium.
The main thing from my point of view is that it isn't rotting!

cheers

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I'm gonna get flak for this... But... Try a PH of 6.0.

I kept having problems in my hydro at- 5.5, 5.6, 5.7, 5.8.

5.9-6.1 I seem to have a very happy spot. Contradictory to what I have read over the years.

Make sure you aren't changing the buffer of your water either. If you buffered it to 5.5 it'll always creep back to that. Maybe aim for a buffer of 5.8 and see how you go

eyderbuddy said:

Looks like light stress to me (toasty leaves curling upwards), are they too close the lights? I've seen the same symptoms in plants getting within 6 inches of LEDs.

I'd only worry about bud rot if your humidity is constantly over 65%

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Yes some of the bud sites have got quite close to the cobs. I was a little slack with my scrogging on this run so nearly ran out of headroom. I would like to think it is that simple but the canopy is quite un-even & I am seeing clawing on leafs that are close to the cobs (you would expect) but also on those further down that seem to be getting about 40000 lux which to my mind should not cause them any issues.
That all said & done I have dialled down the wattage a tad just as a precaution.

slinkysaurus said:

I'm gonna get flak for this... But... Try a PH of 6.0.

I kept having problems in my hydro at- 5.5, 5.6, 5.7, 5.8.

5.9-6.1 I seem to have a very happy spot. Contradictory to what I have read over the years.

Click to expand...

Interesting I have seen a few people advocating that over the years on the forums but never tried it. I've just flushed, decreased wattage & bumped the calmag levels so I'll let it ride for a day or two & if no joy I'll give the ph increase a go.
Consensus here seems to be that it is not rot which is the main thing. I can deal with slight feeding imbalances where as writing of a crop due to rot would be a nightmare.

Warm air circulating your room at lights off (and on) is also a good way to lower humidity. Standing fan and an oil heater. Blowing through the tops of the plants. Try keep that humidity at 45% tops for flowering. If you don't have massive coke bottle colas, then you should be safe from rot where you're at. I woops still like to see that lower humidity tho

kushedy said:

Interesting I have seen a few people advocating that over the years on the forums but never tried it. I've just flushed, decreased wattage & bumped the calmag levels so I'll let it ride for a day or two & if no joy I'll give the ph increase a go.
Consensus here seems to be that it is not rot which is the main thing. I can deal with slight feeding imbalances where as writing of a crop due to rot would be a nightmare.

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FYI Leaf curling from light is a totally different curl. It curls the entire perimeter edge of the leaf and browns it. You just have tips and a few rust spots that would say a cal mag deficiency and base PH problem. Adjust your PH, leave your lights

slinkysaurus said:

FYI Leaf curling from light is a totally different curl. It curls the entire perimeter edge of the leaf and browns it. You just have tips and a few rust spots that would say a cal mag deficiency and base PH problem. Adjust your PH, leave your lights

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Some of the buds further up have leaves browned like you just described. Well it was 5.8 when I just checked it. I'll bump it up a tad & monitor. Thanks for help. I'll update when it gets better or worse (hopefully not).

kushedy said:

Some of the buds further up have leaves browned like you just described. Well it was 5.8 when I just checked it. I'll bump it up a tad & monitor. Thanks for help. I'll update when it gets better or worse (hopefully not).

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5.8 buffer is okay, it's not as bad as 5.5! We can read a thousand different things to try. It's only actually trying them ourselves do we find out what really works. Keep us posted

No improvement. I would say they look slightly worse. That said it is early days for the changes to take effect.

I checked the temps & humidity as the lights went on this morning & temps were 64f & humidity was 65%.

I’m wondering if the roots are getting to cold at night or maybe need a dry period. They’ve been fed by drip 6 times a day for most of flower so have not had a dry day at all. That’s no different though from how I normally run bar it being colder at the moment during lights off.

I am curious thought about the purple/brown colour some of the leaves are going which can be seen in the 2nd photo.

I just realised you're in soil? Drip feed yes? If it's hydro Drip feed that's NOT what you want. The drips fill the rock wool with water and it rots the root anytime after seedling stage. Take your PH up if that's the case to suitable soil PH levels of 6.5.

Secondly, that top looks heat burned or you have a root problem. Cold wouldn't cause that, but heat will, or bud rot will.
Inspect that bud very very closely. Your humidity is also still very high at lights off

I'm in coco coir. 50% coco 50% perlite to be exact. I'm intending to leave a tube heater on in there tonight going forward. I have inspected the buds & I can't see any rot, touch wood. I've switched off the pump in the res & am going to let in dry out for a day or two. I may brew up a bennie tea for it.

Yeah in that case I gave you some duff advice. I'm really sorry. You do know your PH should be over 6 at the least in soil? I don't know why I thought you were hydro :/

Next step, seeing as there are some green good looking leaves on there, is that manky bud all dry and crispy?

No, I'm not in soil & yeah, I know that with soil 6.5 is meant to be the ideal ph. point. I'm in coco coir so supposedly 5.8 is the ideal ph level.


No, the buds haven’t dried. They are still sticky.

kushedy said:

No, I'm not in soil & yeah, I know that with soil 6.5 is meant to be the ideal ph. point. I'm in coco coir so supposedly 5.8 is the ideal ph level.


No, the buds haven’t dried. They are still sticky.

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I need to read better befofe I reply haha!I'm getting stumped. I hope you find out what the issue is.
All you can do is bump your PH either way until you find a suitable spot. Or as you say try giving ten some drying time. If the PH is good it doesn't take long for them to show signs of relief.

Come to think of it, I kinda had the same problem as you with my buds when I tried growing G13. I think they were super sensitive to micronutrients and the heat was too much