you can flower at any time you want. i would move your light up some tho, a couple of your plants look like they have some heat stress. and a couple over watered or need to be watered, by the leafs dropping. whats the strain? whats the soil?
Mixed seeds all bought off attitude, 6 are OG Kush. Then one each of EZ Sativa, Northernlights Blue, Headband, annd Super Lemon Haze.
And for soil I'm using Subcool's super soil the 2010 version. The plants aren't in mint condition, I know its only my 2nd grow. Compared to my first I'm ok with how they're doing. Heat at the canopy level has never risen above 71* so thats why I've lowered the light to about a foot away. I'm still experimenting alot, really not expecting perfect plants yet.
I'm mainly just concered about when to flowered, worried about vegging too long and not having the light to cover the canopy. So if anyone has experience flowering around 10 plants under a 1000 watter it would really help.