Soil erosion can be a serious issue in eastern Canada during the 3–5 wk that it takes for potato (Solanum tuberosum L.) to emerge under the cool, humid climatic conditions with frequent heavy rainfall events. Seeding a fast-growing nurse crop at the same time as the potato crop can hold the soil particles in place, reduce surface crusting, and increase water infiltration. The objective of this study, conducted in Prince Edward Island and in New Brunswick in 2017, was to evaluate the effects of under-seeding potato with barley (Hordeum vulgare L.) and winter rye (Secale cereale L.) on marketable potato yield, nitrate dynamics during the growing season, and soil moisture content. Nurse crop growth was terminated mechanically (hilling), with a selective herbicide, or with a nonselective herbicide. Yield increases ranging from 9% to 91% were observed when nurse crop growth was terminated using a nonselective herbicide at both sites. Inconsistent results were obtained when a mechanical method or a selective herbicide were used, with marketable yield reduced at one site and no effect on yield at another site. There was a trend toward higher soil nitrate contents under the control than under the nurse crop treatments, though it was not consistent across sampling times. Results demonstrated that there are circumstances under which nurse crops can be successfully integrated into a potato-based system and provided future hypotheses to test. Potential confounding factors that can impact the nurse crop efficiency are discussed.