When to start Nutes..?

im starting my first real soil grow soon and im planing to use canna Terra nutes. im just woundering when do i start adding nutes? of course when it starts yellowing but when i tried that last time they dident realy recover again they did ok but i think they can do better. on cannas feeding chart they show feeding from te getgo and the ec is wery high and they dont say to feed every other or every watering so im alittle bit comfused and need some help thanks....

http://www.canna-uk.com/growguide

and btw ph is recomended at 5,8-6,2 isent this alittle bit low?

i add nutes when the first two round leaves start dieing off