I agree with the other posters, what kind of light/how bright/how many hours are you giving them? I see also that some of them look like you harvested already and are re-veging the harvested plants. That might make them go into the flowering phase easier, I'm not sure because I always kill the plant when I harvest. Are you doing that with some of them or am I just seeing things?
Also, some of those seedlings that you have tied up to the stakes are really stretched out. That is another sign that you don't have enough light on them. When you transplant those, bury those long stems up to an inch or 2 under the cotyledon leaves so they can stand up on their own.