How often should I apply dr.earths bud and bloom b...

Only thing I can suggest is to follow the manufacturers guide, which is not normally something I'd do. Got some good reviews on amazon. I don't like using these fast and slow release nutes as once it's in you have no control if it starts to burn badly. How have you fed it in veg? Same brand but a veg nute? Your plants look really healthy from your pics, So best I can say is wait for the leaves to show you it's hungry then chuck it in. From a quick google it says it has fast and slow release nutes, so the fast takes care of the initial fading then I suppose feed's it as and when it needs it. Will follow along, would like to see how this stuff works out for you. Good luck