First Grow 00 Seeds Northern Lights

Day 15 the day after transplant and the second plant is still showing a yellow tip on one of her leaves. Initially I thought it was caused by heat stress. Now I am leaning towards her needing more water as I started to give her less water after the yellowing leaf. I am not smart. Plant 1 is doing well! I am thinking of topping her at the 5th node as she is healthier. The second plant will get some LST as I am trying to maximize the small space I have (2x2x4). I watered them each with 6.4 ph water at about .33 gallons per plant, just enough to see some runoff from the bottom of the pots. Day 16: Not much change, uploaded a new view of them to show stem and node spacing. Next watering will include 1/4 power FF nutrients. Day 17: No significant changes, soil still damp so no water. Day 18 Small growth, gave light watering at 6.4 ph and light spray. Day 21 Plants were dry so I watered with 1/3 strength of recommended feeding from FF.