It really depends on how big your plant is before using it. You for sure dont want to use grow big right out of seed. If your plant is 2 weeks old and about 10 inches tall you can use 1/4 strength no problem. Big bloom is a flowering nutrient. Obviously you could use nutrients whenever you felt like it but why waste them when they arent best utilized? There is no intrusion. We are all friends here. I want to help the absolute most amount of people I possibly can. I am by no means a expert like a person who has been growing 30 or 40 years but when I want to learn something I really go to work on the endeavor. Easily over 50% of my day for 4 years with no breaks has went to learning,experimenting,reading,watching grow dvds,laws on how to deal with the police,water quality just anything I can get my hands on. Literally everywhere I go Im thinking of growing passing regular everyday situations wondering what it would be like to have a room of such and such size and what I could do. I love growing and I love being helpful even more. I went from 1 monitor up to 3 just so I could research more at once. Sorry I guess this sounds like me trying to sound impressive or inflate my ego but honestly I was just trying to make a point plus I just smoked a bit of what I clipped off last night so might be more talkative then I normally am. Where was I?
Oh yes no need to use nutrients before they are needed. The plants will let you know how they are feeling you can learn to read them. Keep in mind people veg for a different length of time. My current journal I vegged for 1 month. The most I vegged for was 3 months but that gave me a 5 foot bush and that isnt realistic for indoors especially back then when I wasnt as experienced as I am now and was afraid to defoliate it was just ridiculous. Anyways, you didnt intrude I rather be asked the same thing by thousand people then have 1 person not ask and mess things up for themselves. Take care