Low adoption to cover crops in the northern Plains is due to limited soil water for stand establishment, short growing season, and few adapted winter-hardy species. Studies were conducted to evaluate the impact of interseeded winter camelina [Camelina sativa (L.) Crantz] and winter rye (Secale cereale L.) using different soybean relative maturities, planting date, and row spacing on cover crop biomass, canopy coverage, plant density, soybean yield, and wheat (Triticum aestivum L.) yield the following year. Early-maturing soybean cultivars, produced increased cover crop biomass and canopy coverage, with winter rye outperforming winter camelina. Row spacing showed no effect on cover crop growth, yet narrow rows produced higher soybean yield. Spring wheat is not recommended to plant following winter rye, yet there was no negative effect from winter camelina. Interseeding cover crops into soybean in the northern Plains is possible, but relative low amounts of fall cover crop biomass is produced.