Rootstock vigor is strongly influenced by environmental conditions during the early growth phase. Light intensity plays a critical role in determining the vigor and physiological performance of plants under controlled environments. The aim of this study was to evaluate the effect of light intensity on the growth and root system of two tomato rootstocks. The present study evaluated the biometric responses of two commercial tomato rootstocks, Auroch and Ficus, to three light intensities, i.e., 150 µmol m⁻² s⁻¹, 250 µmol m⁻² s⁻¹, and 350 µmol m⁻² s⁻¹. Biometric parameters, including plant height, root length, stem diameter, leaf area, and fresh biomass, were measured and analyzed statistically. The results indicated that light intensity had a significant effect (p value < 0.05) on all growth parameters. The tomato rootstock Auroch performed best at 250 µmol m⁻² s⁻¹, where leaf area expanded to 118 cm² compared with 41 cm² at 150 µmol m⁻² s⁻¹, and shoot biomass increased from 1.0 g to 3.7 g. In contrast, Ficus responded more positively at 350 µmol m⁻² s⁻¹, where root biomass increased from 0.19 g at 250 µmol m⁻² s⁻¹ to 0.65 g and root length exceeded 25 cm, compared with 11.7 cm at 150 µmol m⁻² s⁻¹. The initial findings indicate that light intensities exert a differential effect on tomato rootstock growth. Auroch favored moderate irradiance for balanced shoot and leaf development, whereas Ficus performed optimally under elevated irradiance with stronger root growth. These findings refine our understanding of tailoring light management strategies for different rootstocks to improve seedling quality and sustainable tomato production.