The use of polyethylene tarps is becoming popular for urban and small-scale vegetable farmers to manage weeds through occultation. Similar tarps can also be used as plastic mulch in high tunnels during the growing season. However, little is known about how this will affect crop productivity and soil moisture retention. Trials were conducted in 2022 and 2023 to determine the effect of white silage tarp, black silage tarp, paper mulch and black landscape fabric as compared to bare soil for lettuce and tomato grown in high tunnels. Two lettuce varieties (red and green) were planted in a split-plot randomized complete block design in the fall and tomatoes were grown during the summer. Soil samples were used in combination with soil moisture meter readings to determine gravimetric and volumetric soil moisture content throughout the season. Tomato trials were conducted in six high tunnels and six open-field plots. For both crops, harvesting occurred to monitor total, marketable, and non-marketable yield. According to a one-way ANOVA test, there was not a significant treatment effect in the 2022 lettuce trial. However, the 2023 lettuce trial revealed that white and fabric treatments were the most effective at conserving soil moisture. On average, there was 2.6% higher soil moisture in plots with white silage tarp and black landscape fabric as compared to the bare ground plots. In the high tunnel tomato trial, the bare plots had significantly lower volumetric and gravimetric soil moisture levels (P
