Polyethylene plastic mulch is widely used in organic horticultural systems to suppress weeds and promote crop performance through optimization of soil temperature and moisture. Unfortunately, disposal of this non-biodegradable material is associated with negative environmental impacts that are misaligned with goals of organic agriculture. We propose to develop biodegradable alternative mulches that effectively suppress weeds, but also enhance or maintain soil health while mitigating plastic pollution.With producer collaboration, we conducted exploratory studies to assess weed suppression associated with a simple cellulosic mulch applied as an aqueous slurry (hydromulch) in organic carrot production. Our study, along with others, showed promising results, but with room for improvement. We propose to conduct experiments, also in collaboration with organic producers, to develop new composite hydromulch formulations – optimizing physico-mechanical properties such as tensile strength, puncture resistance, rain-fastness, porosity, C:N ratio, and soil adhesion. We will explore, with producer involvement, novel application methods for installing hydromulches in organic blueberry, strawberry, onion, and broccoli production systems. Weed communities will be assessed in each crop to determine hydromulch efficacy. Comprehensive soil measurements will document hydromulch impacts on numerous soil health metrics. Cost-benefit analyses will document economic benefits associated with hydromulching.To accomplish these objectives, numerous experiments will be conducted in both controlled environments (laboratory and greenhouse) and in the field. Types of data that will collected include weed density and biomass under various mulch treatments, mulch deterioration, crop growth and yield responses, mulch physical properties, and soil responses to mulch presence, incorporation and decomposition. Economic data will also be collected about the cost of using these approaches in a production context.All these data collected are stored and available as *.csv files that are titled according to datatype and contain comments explaining treatment codes, units, and other information that facilitates use of the data.