Sweetcorn is a high value crop that can grow almost anywhere given the right temperature conditions. In North Dakota those conditions are not always met. Using mulch increases the soil temperature. Early planting will have a higher soil temperature increase, but also creates risk from frost damage. In this study, three varieties of sweetcorn was planted with different maturity days, on four covers (black, clear, biodegradable and no mulch), with four different planting dates (from April 15 to June 1). Emergence, growth stage, plant height, leaf area index, soil and near surface air temperature, yield and sugar content was measured. The germination rate was shortened for the clear mulch by 2.6 days. Through this one year study, we can say that mulch is effective in raising soil temperature, increases early growth for 84 day variety and increases fresh yield for all mulch covers when compared to the no mulch treatment.