Boy it sure looks like somethings eating it.
It looks like leaves here and there, not through the whole plant.
I only grow indoors so not sure but I'm far from an expert too.
Wish I could help more.
If that's a hempy,do a flush with ph water for a day.
try lowering ph down a little more to 5.9, 6.0
good luck
someone with more experience will help I'm sure.