The unmulched plots were hand-weeded four times over the growing season. No effort was made to control weeds in the mulched plots. Although, clear plastic mulch may result in an increase in soil temperature, the presence of light led to the disadvantage of weed growth, while the absence of light with black plastic did not allow photosynthesis of weeds under the film and therefore weed growth was suppressed. This result was in agreement with that found by Lamont, 1999 and Lamont, 2001.