1st grow room help

"Sour diesel" autos. 7 days ago they spouted out of soil. Promix hp, coco and perlite mix. I think my original humidifier wasn't working properly. They were stretching, then I found info online that said add more soil around the stem (ant hill style), and adjust the lights ...so I did. My...

Was wondering why I'm getting little lines in between the leafes. (pic 1 and pic 2) Seems like the plant is doing ok. Its been day 9 since i switched to flower. Temperature has been reaching 82-84f in the day but normally i keep it 79° early when lights turn on and then slowly go up to 80-83...

im growing 2 plants do I even need a carbon filter? If I do what could I use instead?