Spring-planted green manure cover crops may provide a nitrogen (N) benefit to a subsequent sweet corn (Zea mays L.) crop, but spring growth and lack of consistent benefits documented in previous studies provide limitations to adoption. Berseem clover (BC; Trifolium alexandrinum) and chickling vetch (CV; Lathyrus sativus L.) are two legumes that could be beneficial when spring-seeded, but they have not been well studied in this context. The objectives of this study were to measure spring-seeded cover crop biomass and N yield, and the subsequent effects on sweet corn yield and response to N fertilizer.