This thesis is an investigation of the effects of wavelength specific lighting on tomato growth and source leaf photosynthesis and export. Plants grown in a greenhouse during the winter months under ambient or supplemental lighting showed little difference in whole plant or leaf net carbon exchange rate nor carbon gain. However plants grown under supplemental lighting produced statistically higher biomass and flower bud production. Differences in transpiration rates and water use efficiency were determined when plants were analyzed red-blue and red-white lighting treatments. An increase in daily export rates was seen under red-blue and blue when compared to white or red light treatments of white light grown plants. These increases in export rates indicate a direct effect on the export rates solely based on spectral quality. Results from this thesis aim to increase the understanding of wavelength specific lighting effects on tomatoes and help aid in optimizing the light spectrum for greenhouse production.