This is an excerpt from:
“Spectral characteristics of lamp types for plant biology”
March 2013
Jacob A. Nelson and Bruce Bugbee
Crop Physiology Laboratory, Utah State University, Logan, UT
Ties in with what you’re saying @Ca++
“The ratio of YPF to PPF ranges from 0.89 to 0.91 for most light sources. Higher values for this ratio (0.95; HPS lamps) indicate that plant growth might be slightly better than the PPF as measured by a standard quantum sensor.”
“Spectral characteristics of lamp types for plant biology”
March 2013
Jacob A. Nelson and Bruce Bugbee
Crop Physiology Laboratory, Utah State University, Logan, UT
Ties in with what you’re saying @Ca++
“The ratio of YPF to PPF ranges from 0.89 to 0.91 for most light sources. Higher values for this ratio (0.95; HPS lamps) indicate that plant growth might be slightly better than the PPF as measured by a standard quantum sensor.”