When to start feeding if looking healthy?

Im growing in Biobizz soil, been vegging for a month in 11litre pots and plants look absolutely lovely. Im about to switch to flower. I have Biobizz grow nutes but didn't use it.

My question is, would the nutes have have any benefit or is it a case of if it ain't broke don't fix it?

sooner or later the plants will suck up all the nutrients from your soil . if they look great . and your going to switch , I would just go 1/4 strength of normal. why ? because you don't want to let them go hungry and then your trying to catch up . and you don't want to over feed them possible burn them . this is my opinion,

If they look healthy I say let them be. Your plants will tell you when there hungry