More info needed.
What's your grow set up......? Lights, temps, soil, hydro?
What are you feeding them?
They look a tad overfertilised to me.
There's a bit of foxtailing going on too, probably stress related
Maybe raise your lights a bit and if in soil just give them water only for a few waterings.
And back off on nutes.
You've at least another 5 weeks to go