i feel like six plants should be a little denser, maybe try hanging your light a little lower then moving it up as they grow. dont move it to close though as the plants will get bushy and not too much taller. just a thought. for faster growth light is the most important part, the amount of light available controls the speed of metabolism within the plant along with natural things like oxygen and co2 and just the right reserve of nutrients till they get big then they're fat girls n eat like um too. yours are past that point but strongly recommend the light suggestion