Canoeing leaves (cupping up)

[Teacherttom]

Hi all,
I'm very new to this, and I'd like to know whats happening with my pot. Switched to 12:12.
I have consequently reduced watering. No added ferts. Lights are about 45cm away. Mg def? Please Help.

Thanks everyone.
Nish

Haha, by now I'm sure you found your mag deficiency ... but info is info! I know this is 4 most old..but info is info

 

[Icemud]

Generally when the leaves "taco" its an indicator that the plant is too hot and trying to cool itself off. (similar to after playing sports and you put your arms up in the air to catch a breeze on your armpits). This is not always the case, as some genetics/strains do this regardless of environment. I would first make sure you have good airflow through your canopy, check your light height and make sure they aren't too close as vegging plants don't need a ton of light. The leaves look like there is some deficiencies going on so I would check your medium ph and feeding ph as well. Most likely its a combo of too much heat, too little airflow mixed with a low RH.