Hi Aki, Canna Terra Pro it's good for whole vegetative stage but, for flowering , plants need more and specifics nutrients that soil doesn't have...
Depends on the soil, how organic, what's in it. We use (sparingly) high phos nutes in organic soil as a boost between veg and flower for autoflower strains. Those maturing within 60-75 days, not an appreciable difference. Autos (super autos) taking 90+ days to finish, that added boost helps in the long haul of maturation.. Likewise, we've grown just strictly organic soil (with amendments from the get-go) and have harvested many an auto garden.
To each their own...adding in flower stage...or not.