Your bloom complex should provide enough N to avoid deficiency in flower...
If the stems are only red on top and green on bottom, its a sunburn which is normal and not really harmful.
Assuming it's a sunburn, you either have micronutrient deficiency due to not giving her any micros, or it's a micro lockout caused by too much PK. Again, this is only if you have a sunburn and not red stems caused by phosphorus deficiency.
You should know which, good luck!