Help PLEASE! Look at this leaves :(

[HKbadazz]

Fifth week of flowering. Mostly big fan leaves turn like this please help what does it need?
http://i1203.photobucket.com/albums/bb396/Huynhh87/138e67b5.jpg

Fyi: just started organic worm casting fertz last week on these plants.
Thank u in advance.!.!

 

[itzjesus]

From what I've read around, not 100% sure on this, it uses some of the nutrients from lower fan leaves to "Grow" bigger buds? So the fan leaves dry up & fall off.
1st post woohoo

 

[evilpyro26]

Looks like a phosphorus deficiency to me.

 

[Beansly]

Looks like a phosphorus deficiency to me.

yeah could be. Looks like it.
View attachment 1540069

 

[IVIars]

From what I've read around, not 100% sure on this, it uses some of the nutrients from lower fan leaves to "Grow" bigger buds? So the fan leaves dry up & fall off.
1st post woohoo

No leaves should fall off. yellowing towards the end of flower is fine, but not yellow and fall of