. 2019 Sep 13;10:1114. doi: 10.3389/fpls.2019.01114

Table 1.

Photosynthetic photon flux density of supplemental lighting treatments during the day and night periods as measured above plant canopy (1 m below the LED fixtures).

Light treatment	06:00–18:00h		18:00h–06:00h		Daily light Integral (mol m⁻² d⁻¹)
Light treatment	Red (µmol m⁻² s⁻¹)	Blue (µmol m⁻² s⁻¹)	Red (µmol m⁻² s⁻¹)	Blue (µmol m⁻² s⁻¹)	Daily light Integral (mol m⁻² d⁻¹)
12 h lighting	200	50	0	0	10.8
Continuous lighting	200	0	0	50	10.8

Peak outputs measured by a spectrometer (Flame spectrometer, Ocean Optics, Dunedin, FL, USA) from the red and blue LEDs were 660 nm and 447 nm, respectively.