maroon stalks!

..got a 2 part question. i havet to 2 month old girls one has a pretty intense dark stem and the other not so bad. both are not growing well and the one with the dark stem has some wacked out deformed leaves with black tips. what is the probalbe cause and can they turn around?

Just the strain bro but post pics,ive had plants go from green to a deep almost black purple,pretty cool to watch

...some say strain, some say low temps...I say both can be a factor.