flowering plants top leaves cupping

so my white fires have been flowering for about 3 weeks now, the first couple they were all looking healthy but about a week ago i started to notice the new leaves were starting to cup, but i wasnt sure if it was just cause it was such new growth. Unfortunately it grew out and turned out way worse looking, and i also noticed the older growth and fan leaves are starting to cup around the sides as well.

Bump.
You and me both! I've been trying to pin this down for a couple of weeks now. It only happens to one or two plants.
So far the reasons I've found trawling the net
1. Over/under watering
2. Temps too high
3. Humidity too low
4. Magnesium deficiency....

Nobody seems to know

Aww man I hate when It could b a variety of things, guess Ill just have to try and wait it out... On some of the leaves it's looking really bad though

what are you using for soil,fertilizer?

Seems like my sativas will cup easier and usually it's something I've done. One of mine cupped so bad it hurt the buds and yield really bad. I think I did it by adding too much bloom formula when it wasn't use to it? Good luck and easy on the nutes / ph.

Let's eliminate the problems. I have the same issue. I'm running a 1k hps in a 4x4x6.5 tent. My temps never get above 78-80° and my nighttime lows get down to 58°. So I'd say it isn't temp related. Humidity? Possibly. I live in SD and the humidity is low. So low, that since moving here I've gotten the worst case of dry scalp. I believe it has something to do with the intensity of the light. What's your setups like? The only leaves on mine that are effected are select ones, closer to light, directly under strongest penetration. Sound close to yours? What's different?

I don't think it's light intensity; I have differing sized plants, 1-3 feet from my cool tubes.
I'm running 2 x 400w cool tubes, soil. (Strangely, I don't recall having this problem with hydroponics)



(Edit) My humidity is generally high, if anything (it rains every other day here )
I shall post my min/max figures for temp/humidity later, when the girls have woken up...

The only plants it seems to be NOT effecting of mine are the ones closest to the light, it could be humidity cause I keep my dehumidifier on high to keep it under 40% but I'll turn it down a lil and see how it goes... Also I'm using half happy frog half ocean forrest

Temperatures for the last 24 hrs; Max 27oC/80 F Min 14oC/57F

Humidity; Max 69% Min 37%.

I think we can rule out light intensity and high/low humidity...
I'm going to stop all watering and see how things go when she gets very dry...

Doesn't seem to be getting worse....but famous last words eh?

that rams horn looks like a nitrogen overdose. but i could be wrong brother

I'm favoring it being over watering at the moment

http://www.ilovegrowingmarijuana.com/plant-moisture-stress/

I don't think it's N toxicity....bloody hope not, as all that can be done then is flush and ride it out. And I have other plants, same strain/age/soil mix, that would be displaying the same symptoms if it was soil based...

it may be overwatering too, your definately not wrong. if your doing hydro, its probably pushing more towards N. what are you feeding the plants for flowering?

They're all in my organic soil mix....I haven't fed them as they haven't asked yet. And, like I say, their sisters are all fine and in the same environment...

That looks like claw leaf to me, I going with urgod on the nitrogen overdose.

The ones closest to the light may not be affected because they air receiving more light than the out permiter of your grow and probably more heat making them transpire more, thus meaning they are growing with more intensity and will consume more nutrients and need watering more often. They dont all respond the same. I bet your outer plants are all dark green around the perimeter and as you get closer to the light they get lighter and ligher colored, just a hunch.

Its time for them to put on weight and nute overdose will kill your yield, flush your medium in the affected plants and tone down their nutes a bit.

OVER WATER. you said the wones closest to the light were fine so you giving your plants feed same time and same volume every time so you are over watering the ones away from the light becuase they wont drink the same as the ones near the light so give them less or put another light like the others problem fixed, i had same problem few weeks ago i poted in bigger pot and trimed those shitty leaves and watered just top of pot untill seen new growth then increased water half of pot and then back to normal feed to runoff worked for me .