Need Some Help

I was wondering what problem I'm having with this one particular plant. All the rest are growing fine but this one. I have a pic attached to see the problem.

Thanks
Joe

Let me check my crystal ball......hmmm.........it says you need to give more details....

hey at least he gave us pictures...but yeah detail us out your grow, from medium to lights and everything in between, watering schedule, strain of weed if known, temperature, humidity, light cycle, etc etc etc...the more details you give the better your answer will be

With just a pic to work with, it'll be tough to diagnose.
From looking at the twisted new growth, it might be a copper deficiency,
But without more info there's no way to say for sure.