Weed Suppression and Labor Costs Associated with Organic, Plastic, and Paper Mulches in Small-Scale Vegetable Production

Abstract

ABSTRACT The effects of several mulches on weed growth and labor costs in small-scale, non-mechanized vegetable production were compared. Hay mulches applied at 15 to 24 Mg ha−1 (ca. 100 mm depth) several weeks after tomato (Lycopersicon esculentum Mill.) planting substantially reduced the growth of annual weeds, and sometimes resulted in a net labor saving compared to the unmulched treatment. Grass seed carried by hay contributed visibly to weed growth in only one out of eight trials. A mulch of composted yard waste at 117 to 196 Mg ha−1 (ca. 30–50 mm depth) was less effective against weeds than the hay mulch. Black plastic (32 μm thick embossed black polyethylene) blocked weeds except for a few emerging through planting holes. Labor requirements for mulching (including end-of-season removal) and transplanting were greater for plastic than for organic mulches, so that no net labor savings were realized. Alleys between plastic-mulched rows also required other weed control measures. Kraft paper mulches decomposed before the end of the season, and thus provided less weed control than plastic. However, two layers of newsprint laid under hay or straw significantly enhanced weed suppression by the organic mulch.