When to start using blooming nutes

When should I begin to administer a blooming fertilizer? When I determine the sex? When I see the first signs of flowering? or when the plants enter a 12/12 light cycle. I also read that I should still use high N nutes when I start using the high P nutes and then gradually stop using the high N nutes. Can I please get a clarification? Thanks in advance.

Start fert bloom after you go into 12/12. I haven't tried tapering off myself, I just flat out switch it up.

start using your bloom nutes 2-3 weeks into flower or when ur start to see bud sites forming