Lack of attractive short-term economic returns to growers and limited time for cover crop establishment following maize and soybean harvest are major reasons for slow cover crop adoption. Therefore, alternative cover crops and seeding practices are needed to provide immediate economic incentives to growers and extend the time necessary to establish cover crops in maize–soybean production systems. Successful establishment of pennycress (PC) and winter camelina (WC) as covers following short-season small grains, and the ecosystem services they offer is well documented. However, the impacts of interseeded PC and WC on soil N, cover-crop biomass C, and N accumulation are limited. A better understanding of the ability of PC and WC to scavenge soil N when interseeded in standing maize and soybean as cover crops is needed.