lol here we go again eh? though the posts are getting smaller and we tend to agree on more things ![Big grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
We tested different combinations of light (different types of hps, hps/mh, mh, CMH, plasma, plasma/hps, and came to the conclusion that there still is a direct relationship between the ppfd and the yield. The differences were not significant. The quality and morphology of the plant however was very different. We needed 200 watt extra MH compared to a 600W HPS to get about the same ppfd at canopy height. So I would say in general HPS is the most efficient light for production, but to get a good yield and a good quality you need to look at the quality of the spectrum too. Temperature (and leaf temperature) is also very underestimated. Stem elongation is also increased by high day/night temperature differences.
We tested different combinations of light (different types of hps, hps/mh, mh, CMH, plasma, plasma/hps, and came to the conclusion that there still is a direct relationship between the ppfd and the yield. The differences were not significant. The quality and morphology of the plant however was very different. We needed 200 watt extra MH compared to a 600W HPS to get about the same ppfd at canopy height. So I would say in general HPS is the most efficient light for production, but to get a good yield and a good quality you need to look at the quality of the spectrum too. Temperature (and leaf temperature) is also very underestimated. Stem elongation is also increased by high day/night temperature differences.