hey hotshit, when you gonna move your poor plants off the cold ass concrete floor and start growing??!
you really dont think that your sheet of plastic is insulating a cold ass slab of concrete in winter do you?
come on man. like ive said before, your chasing problems that arent there. your problem is cold roots. i know it sounds too simple. but your spending all this money and wasting all this time and nothing is working. well, getting the plants off the cold concrete floor should have been the first thing you did. the plants would be back on track by now.
a slab is gonna be like 10-15 degrees colder then it is outside. even if you have it 100 degrees inside your room. this is winter time bro, i bet your roots are in the 50's.
been doing this a long ass time man. ive been in your shoes, and your chasing all these problems that rookie ass kids are telling you because they read about it online. offgassing?! hahahaha come on.
i think your problem is the 4 degree shift in the earths axis after the earthquake in japan.