Can anybody tell me what's wrong?

Nute burn,try flushing it

 

many leaves yellow and die as the plant begins flowering, it takes it's nutrients from the leaves and puts them to the flowers. some people believe in trimming during this time, some say it should be done only as the plant lets them die, if you let the leaves turn brown and dry they pull off easily like naturally.... you also might be going too strong on nutrients, do you use chemical or organic fert?

 

Apply 20 or 30 grams of powdered milk in water and drench.

How often are you irrigating? Did down and see how the soil is at 18 inches or so.

Most folks, especially newbees, but even the most experienced grower, over irrigate.

 

Someone is pulling your leg guy. That mottling is not from a plant maturing in flower...

 

any chance you could post a pic of the entire plant?

 

@ROC-DOGG
It's fine.. Very normal for some plant strains to start dropping the big fans come mid August outside..
My Blue Berry starts dropping them very early it's just her way I've come to know and accept it from her..
BNW

 

That pic is kinda small, but from what I can see she looks good. Overall she looks really healthy. I wouldn't worry too much about the nute burn. I had the same happen to one of my plants. Here is a pic of my affected plant when the nute burn was the most visible and here is the same plant ten days later. All I did was give them hose water every two days when the weather was dry.

 

Looks beautiful too me!