what i have been giving her is this espoma plant-tone which is 5-3-3 so it's hard to believe there is a nitrogen deficiency.
http://www.lowes.com/pd_79144-1321-PT8_0__?productId=3043968
its in soil?
if so how long has it been in it
did you use dolomite in your mix ?
what are you giving for cal / mag ?
N def presents from bottom up; this is diffuse yellowing. I don't like the size of that pot for such a large plant, I hate time-release ferts. I use totes, twice the size of that pot, for big plants.
just my opinion brother
but id start with ph