What's the cause of this??

Was hoping someone has came across this because am stumped never seen it before any help would be much appreciated cheers

That looks like major trouble. No clue. Root damage? Virus? Completely messed up PH?

Is it just me, or does that box only have about 3 inches of soil in it?

i've had that before and the best i can figure out is you had root rot when you planted that clone.
when i had it they looked good for a few days then started wilting, i used a little pool shock, they stopped wilting, but it took about 2 weeks for them to really perk up and start growing good again

Cheers guys it has plenty of soil in it m8 12ltr pot she is still growing but not much better

Over nuted?

That's what a thought animal mother did hit her with a bit to much to start with will it be ok or just take her out? Cheers

I`m literally having the same problem.