ASHS 2025 Conference

High tunnels (HT) are utilized by vegetable growers to extend the growing season and improve the yield and quality of crops. However, concerns about the sustainability of HT soil health can have direct effects on yield and profitability. Recently, growers and researchers have expressed concerns related to soil moisture in high tunnels and potential negative consequences to soil health. The use of non-permeable polyethylene tarps has become popular for urban and small-scale vegetable farmers to manage weeds through occultation. Similar tarps could also be used as mulch, but little is known about how this will affect crop productivity compared to other mulch types. The goal of this study was to examine silage tarps and other mulch types in HTs and the open field to determine how this practice may affect yield and quality of tomato and lettuce. Tomato and lettuce trials were conducted from 2022 to 2024 in HTs and open-field plots to determine the effect of various mulch treatments (bareground, black plastic film, black woven fabric, paper mulch, white silage tarp and black silage tarp) on tomato and lettuce yield and quality. For tomato, harvesting occurred weekly to monitor total, marketable, and non-marketable yield. Texture and organoleptic quality were assessed from 3 harvests across the two years. In 2023, lettuce were harvested and yield data were collected. Leaf color and water content were also assessed. In the HT tomato trials, mulch had the greatest effects on yield during the early season and the application of white silage tarp and plastic film mulch increased early marketable fruit yield by 58% compared to the bareground treatment. Mulch type had no significant effect on tomato or lettuce on the postharvest qualities that were assessed. Our data indicate that silage tarps may be an effective mulch, particularly for HT growers that are looking to conserve soil moisture and ultimately improve soil health. Yield and quality of tomato and lettuce were not penalized when tarps were utilized, and in some cases, yield was improved. As growers continue to adopt practices that help sustain or improve soil health, it is likely that silage tarps and other mulch types can be effective at maintaining crop productivity