Lumens Are For Humans, PAR Is For Plants..?
Lumens Are For Humans, PAR Is For Plants..? The phrase above is among the most misleading cliches in the LED grow light industry. Simply put, both lumens and PAR measure light – one measures the intensity of bands that most register to the human eye, and the other, the total photons of every band in the visible spectrum. Both are important, but both are not equal. PAR values vary dramatically per watt of power in each color band, those in the 625-700nm range, the reds and far reds, delivering the highest readings. They make possible convenient cheats for ordinary LED grow lights, but such methods deliver lights far from adequately balanced to the needs of plants. In fact, cheap PAR...