The FAR-PAR Index Is a Better Predictor of Stem And Leaf Expansion Than Phytochrome Photo-equilibrium

Far-red radiation is on the edge of human vision. These wavelengths of radiation, barely visible to our eyes, induce transformative responses in plants. Moving down into a canopy dramatically increases the fraction of far-red photons, which has implications for high density planting in agriculture. LEDs generally lack far-red because these photons are far less photosynthetically active than other wavelengths. Our research shows morphological changes caused by supplemental far-red radiation