Blueberry needs help!

hey guys this is my dutch passion blueberry tied over, thats in its third week of flowering, nd startin to get some bad leaf color changes on the lower leaves. ne ideas on wat it is nd wat i should do about it. plus rep for advice that helps.

its probably because the container its in looks a bit small in pics .
are you using the right nutes ?

for nutes im just using organic, weaker strength cause the blueberrys are pretty picky wen it comes to their nutes, but i didnt kno if maybe i was using to much nd jus causin a nute burn, or maybe if im not using enough it jus has a nitrogen deficiancy