3 RQS Autos (First grow)

So this is day 14 of my first grow. I forgot to get pictures and make notes during germination, so here we are. Because it is currently cold as all hell at my home, I've had to put a small 55-watt tubular heater in the tent to keep things hovering about 19 degrees celsius. All 3 plants did a fair bit of stretching in the first week, due to me hanging the light too high at the same time as having it dimmed pretty much all the way. I lowered the light and upped the brightness a bit at the start of week 2. Northern light seems to be doing alright, I've noticed some reddish marks on the leaf stems and faintly on the main stem and some of the leaves are a bit of a wonky shape. Sweet skunk is a bit funky looking. It's growing at a slower rate than the other 2 plants and has quite dark and sort of brittle looking leaves. I'm assuming nitrogen toxicity, but none of the plants have been given any nutrients yet and were all germinated in the same soil mix (bio biz light mix). Bubble kush did a fair stretch to the side due to uneven lighting in week one, other than that it seems alright, lower leaves are a little bit dark, but seems alright.