Good evening dude, You're 100% right about the colder temps and the fact that you've been over watering. The lack of heat in you're tent is resulting in lack of water saturation by the plant and the plant is actually feeding off the moisture in the air, therefore meaning you're soil stays wet for alot longer, roots get water logged and that stunts plant growth. I did all of this on my first grow and learnt the hard way. Try up you're temps, water less and try too not worry about them too much, it's a weed, it will grow!
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