Athosanswered grow question 7 years ago In very simple terms: Big lights equals big colas. That and getting the ambient variables right, that been keeping the grow space in the ideal temperature and humidity range.
Overall temperatures; above 23°C (73F), including the night temperatures, and ideally below 29°C (84F).
If you want to get those colas that are 30 cm (12 inches) long and thick as your arms, you would need something like true 600 watts, be it HID or LED.