What lights better for flower

is that a 100w LED? so it isn't really comparable to 400w as far as coverage. you need about 50w/sq foot with hps, but anywhere from 32-40w/sq foot depending on efficacy of the LED. The p1000 is not a high efficacy item, but is more efficient at producing photons than the hps by a fair amount. pound for pound it might cost you less per gram, but you'd get a much larger yield in a larger area of coverage from the 400w hps. No, switching or mixing the lights will not cause the plant to herm. It is smarter to just stick with one or the other. The leaves adapt to the light given, and i'm sure that takes effort to adjust midstream, That should not be enough stress to cause a herm.. unless the plant was already majorly distressed as is... happy plants are robust plants. if doing photos, can do 8-9 sq ft with the hps and maybe 2.5-3sq ft with the 100w LED (i don't see wattage listed). Multiply that by 1.5 for an 18/6 cycle autoflower grow.