I'm the one responsible for the new umol tolerance deviance on the Spectrum Field Scouts. They never had any variance percentages noted for LED, but did for MH/HPS/Fluorescent. Took me a while with a couple of labs but they should now have the new LED numbers in their latest literature.

wow nice setup hydrophotobio I am in on this discussion but will have to get up to speed. your setup for growing grass with out light is cool I have seen them but never up close or in actual use but in advertisements. I have questions can you tell me your building size? what type of outdoor temps you experience? I am trying to grow crops all year round in Northern MN. tell me about your ligts in the picture.