This paper presents the results of a study on the effects of red light treatment of sweet corn seeds on the quantity and quality of the subsequent yield (total and marketable), as well as the length of cobs and thousand kernel weight. The respective groups of kernels were exposed to light: 1—once (K1), 2—twice (K2), and 3—thrice (K3); the control seeds were untreated. The light treatment had a positive impact on the analyzed values. Relative to the control, we observed a yield increase of approx. 5% for the Basin cultivar and approx. 25% for the Shaker and Powerhouse cultivars under the K2 mode. We also recorded an increase in the percentage of marketable yield of approx. 20%, 45%, and 48%, respectively for the Shaker, Powerhouse, and Basin cultivars. Positive effects were also observed in terms of cob length and thousand kernel weight for all treatment modes and cultivars analyzed. The obtained results support the inclusion of this method in the scope of recommendable agrotechnical practices aimed at improving the quantity and quality of yields of various crops and vegetables