Athosanswered grow question 5 years ago Marijuana, no matter the strain, shows a very strong apical dominance, unless TOPed or trained and once you hit the stretch (3 to 4 weeks into flower), the main top will outgrow all other colas. At this point I would strongly recommend applying supper cropping to the main cola to keep it at the same height of the other tops. Also for HID lights, you should have around 60 watts per sq ft; less than that and plants will stretch looking for more light.