Whats this all about?

[cwesto]

My plant is about 1 1/2 weeks thru bloom, under 400w HPS. The newest leaves on my plant up at the tops are all curling inward, like a cannoe and standing straight up to the sky... is this heat stress??? possibly b/c of light too close????

[stinkyattic]

yes

[cwesto]

Thnx SA. I dont get any info with this answer??

[Mr. Clandestine]

If the curling leaves were all over the plant, as opposed to just the tops, then a diagnosis may have been a little different. Nutrient lockout, salt buildup, unfavorable pH, etc. But since you're not seeing it on the rest of the plant, most likely it's just the tops responding to the heat. Raise the light, or bend the stems slightly to get them away from the direct heat. Sounds to me like this should fix your problem.

[cwesto]

My cab is 70F????? Ive been at like 85-90 and havent seen this????

Any other possibilities???

[Ophistello]

sounds like heat, any pics? the leaves reaching to the light is a good thing.

[Mr. Clandestine]

Any other possibilities???

There are lots of possibilities, bro. It's difficult to tell without pictures, knowing whether you're growing in soil or hydro, etc.

Again, unstable pH fluctuations, salt buildup, nutrient lockout...these can all result in leaf curl. So can deficiencies of Magnesium and Phosphorus. If it's an excess nutrient problem or salt buildup, a good flush should help. Followed by a light (1/4 strength) feed.

Also, even though the ambient temperature in the room is reasonable, the tops of the plants can get too hot if growing too close to the light. Try upping your ventilation around the light, bend the tops away from the light, or just raise the light itself.

[cwesto]

Cool thanks alot Clandestine, sounds like a plan my man