When is day 1 of flower?

Its all how you want to run your diary, when I switch my light cycle to 12/12 I classify that as entering flower. I also keep giving it the same feed as i did in veg with maybe some extra P and K as its going to be stretching a lot in the next little while. After the stretch is completed I tend to move over to my flowering feed, but moving forward that's not going to be to much different then my Veg feed as the plants requirements don't change to much. I know of others who will call day 1 flower when they start to see more pistils emerge and stretch starts to begin. There is no right or wrong answer its all for your own logs as long as you remember when you flipped the photoperiod to 12/12 is all that counts. When asking questions about it just let people know when you flipped them as that's a moment of change in its life they can used as a reference point. This topic reminds me of when you you start Germination week and when is week 1 of growth. I like the nuances of it all but in the end it does not really matter. Its the Harvest entry that's king :D Good Luck!