Purpose <p>The objective of this study was to examine the effects of the combined ultraviolet (UV) and far-red (FR) light on the germination, morphological development, and antioxidant properties of chia sprouts.</p> Methods <p>Chia sprouts were cultivated in a customized growth chamber equipped with an automated irrigation system and photoperiodic-controlled light emitting diode panels that included UV and FR (UV-FR)&#xa0;wavelengths. The growth parameters, such as shoot and root length, shoot and root diameter, fresh and dry weight, and leaf area, were assessed in chia sprouts exposed to different intensities of UV-FR light. In addition, the total polyphenol content and ABTS radical scavenging activity were also evaluated.</p> Results <p>The germination and morphological growth of the chia sprouts were inhibited by UV-FR light treatment. Specifically, the weight, shoot length, and leaf area were significantly reduced under higher intensities of the UV-FR light. In contrast, total polyphenol levels and antioxidant responses increased under UV-FR light conditions.</p> Conclusion <p>This study demonstrates a dual response of chia sprouts to combined UV-FR light. Although UV-FR treatments negatively impacted germination compared to a white light control, lower UV-FR intensity was more favorable for morphological development than higher intensity. In contrast, higher UV-FR intensity significantly enhanced the antioxidant properties of the sprouts, leading to elevated levels of total polyphenols. Overall, these findings advance our understanding of how combined UV-FR light can be used to optimize both the growth and functional properties of crops in controlled environments.</p>