Hilfe????

Hi! Are those leaves taken from botton or top of the plant? this may help us. Anyway it seems to me that she is in need for more phosphorus (P).

I see a few different things. With no information all I can do is guess. My educated guess is it is substrate or soil related. Mainly your ph is off or out of range causing lock out.

no diary and no data.. best advice and can tell is ...don't follow any advice people will suggest because this is like playing Russian roulette with your plant =) ... at first look, looks like a K def.... BUT plenty of thing can cause this, so the cure cannot be revealed!