Curling Leaves

[keebler]

I have been growing weed for about 2 yrs in soil and recently decided to try hydro. I have 2 containers going that are doing very well. the one on the left has 11 plants, they spent 4 days in 24 hr light from clone and a fair amount of pruning. The 5 on the right went directly from clone to 12/12 and have not been pruned at all. The left one has been in 12/12 for 51 days and left for 37 days. Just in the last week i have noticed the leaves start to curl up and cant figure out why, here is what i know .....

Nutes - Bumper Crop @ 75% + Carbo Blast
1000 watt supper HPS air cooled light
2 fans for ventilation - one of them pulling air from the room thru the light
2 6 inch air stones in each container
room temp - 60 - 75 F
nute temp 18 - 23 C
Ph - maintained between 5.8 and 6.4
EC - maintained at 15 - 20 1000 - 1400 ish ppm
Nutes changed every week.

5 days ago i changed nutes in both :
11 tub - bumper crop and carbo blast as usual
5 tub - bumper crop, carbo blast, voodoo juice, big bud, and pirahna

It seems to be happening in both tubs so dont think it has to do with the nutes, but not 100% sure. The leaves are curling even on the lowest leaves so do not think heat is the issue. I have checked the leaves with a magnifying glass and no signs of critters. Any info would be greatly appreciated.

[keebler]

the only change i made was leaving the closet door open and setting up a 12" fan to supply more fresh air to the room, although i now believe it wasnt needed, i got to this point without it, it has only been running for about a week and that was just a few days before the trouble started showing on the leaves. I have now removed it. The room temp was only about 75 - 80 degrees with the doors closed anyway. Do you think that a fan blowing on the plants 24/7 for a week would cause the leaves to curl upwards and eventually die. Anyone have any experience with this ?? Is there anyone out there that has a lot of experience with growing that can answer some questions ?? What are the effects of humidity on plant transpiration ??

[dguglielmo]

I am not positive on this but if they are curling up towards the light especially at the tips, does it not mean that they are overheating? Honestly though it is just a guess on a little tidbit of info I have heard once.

[CaliGrower]

Leaves will get all funky in the late stages of flowering. They curl up and die which is normal as the plant is no longer in need of them.

[keebler]

thanks ,over heating would do it for sure but all the leaves are doing it from top to bottom and the bottom leaves are at about 70-75F. And i have plants that are 5wks and 7wks into flowering, 7 ya ok, 5 well they should be going strong yet i think. I looked on my calander and i set a 12" fan in front of them about 4 days before i noticed the leaves. the fan was on low but still blew enough to to move the plants a little. do you think the fan would dry the leaves out and
make them curl up like that.i removed the fan just in case, i only put it there to supply fresh air but it wasnt really needed the light pulls air from the room so fresh air comes in anyway. and they all started to do it at the same time which seems strange.