During 1974 and 1975, experiments using slitted polyethylene mulch were conducted with sweet corn on a Charlton loam soil in Madbury, New Hampshire. Temperatures under slitted clear polyethylene mulch were higher than black mulch or bare soil during the early growing season; differences in soil temperature among mulch treatments decreased as the plant canopy increased. Early growth and subsequent maturity were promoted with clear but not with slitted black polyethylene mulch. Yield increased with slitted clear polyethylene mulch compared with black mulch or bare soil in 1974 due to an increase in number of ears per plant; percent stand was similar among mulch treatments. In 1975, yield increased with slitted clear polyethylene mulch compared with black mulch or bare soil of the 2 May planting due to increased percent stand; no differences in yield occurred among mulch treatments of the 23 May planting when percent stand was similar. At maturity, total accumulation of N, P, and K in the plants was higher under mulches compared to bare soil; no significant differences occurred between slitted black and clear polyethylene mulches.