This study investigates the influence of different red light (RL, 660 nm peak) to far-red light (FRL, 730 nm peak) ratios (1:1, 2:1, and 1:2) on tomato plants, both wild-type and various phytochrome mutants (phyA, phyB1, phyB2, and all combined). It evaluates photosynthesis, transpiration, stomatal conductance, chlorophyll fluorescence, metabolite dynamics, gene expression, and chloroplast structure. Increased RL enhances photosynthesis in most samples except the phyB1 mutant, which also shows increased starch in chloroplasts, indicating disrupted assimilate outflow. Conversely, higher FRL reduces photosynthesis in wild type, despite higher stomatal conductance – a response absent in mutants. Both univariate and multivariate analyses reveal distinct metabolic responses between wild types and mutants to RL/FRL shifts, with more pronounced effects under higher RL. The most significant biochemical shifts occur in the triple mutant. These findings highlight the potential of manipulating RL/FRL ratios to optimize crop growth and quality in controlled environments, offering insights for developing advanced growth chambers and productive plant varieties.