I agree with Leo - light for plants is an area - along with nutrition and to some extent water quality - that can be about as complex as you care to make it. As a geek, I enjoy diving into that stuff, but I think there is a point of diminishing returns for most growers and that cheap efficient LEDs with higher color temperatures have moved that point much closer. I used to have an hour-long presentation on artificial lighting for orchid people covering a lot of technical material. Now it would be one slide that said "buy cheap LED fixtures of at least 5000 K color temperature, up to 6300 K, start at a conservative distance and day-length to avoid scorch, see how your plants respond and adjust accordingly". Far from the complete story, but enough for a lot of people who don't care about the tech-talk. I've bought some fairly expensive LED fixtures with diodes in a carefully selected range of colors to provide the "perfect" spectrum for plants, and I bought expensive PAR meters to check them. They were well-designed and built fixtures and the plants grew well. But I can't say they grew any better than they do under $30 4-foot LED shop lights with a 5000 K color temperature from Sam's. Steve On 2/24/2022 6:46 PM, oooOIOooo via pbs wrote: > There are many factors used to describe agricultural lighting. Technology changes rapidly. Any Wiki page on lighting would be outdated in months. > > ... > > It gets very complicated, which is why I suggest getting a recommendation from somebody who knows about these lights. I don't grow under lights so I'm not that person. But I recognize a lot of the issues. > > Leo Martin > Phoenix Arizona USA > Zone 9? _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>