Finally, the plant is transitioning to flowering. It already smells like lemon balm.
I reduced the nutrient strength to 1.0 EC because some leaves have a dark green shade and claw.
The plant stands under a 100 W Viparspectra LED panel at a distance of around 25 cm.
I applied heavy defoliation this week and adjusted some side branches with garden wire. One branch snapped in the process :/