One thing is light output intensity and another light flux density.

Puntual bulbs, as HPS and MH give very far more intensity the fluoros, wich produces a more evenly light distribution. Intensity refers to how far the light reaches with efficacy. HPS and MH allows to grow taller plants.

The flux density depends of how the light are distributed and the bulbs efficiency. Currently, 4ft fluoros with electronic ballast (wich are cheap and reliable, dont as electronic ballast for HID) have similar efficiency than 400w HPS (and better than MH), and produce a enenly light distribution, wich do them very appropiate for SCROG grow. But 600w and higher HPS are more efficients than fluoros.
knna Reviewed by knna on . Light intensity? Does equal wattage of flouros give as much light intensity as a MH or HPS? For instance, is a 100w flouro equal to a 100w MH in the vegging stage? Could you replace one with the other without affecting crops? Rating: 5