River sediment diversions in the Mississippi River Delta have been planned as a keystone strategy for wetland restoration in coastal Louisiana. The introduction of mineral sediment and dissolved nutrients present in Mississippi River water could drastically alter the abiotic environment of the surrounding wetlands, and the effects on wetland vegetation are unclear. In this study, 50 sods were transplanted from a Spartina patens-dominated brackish marsh into a greenhouse and grown in either mineral or organic soil in combination with one of five levels of nutrient enrichment. The primary component of the mineral soil was silt collected from the bank of the Mississippi River, while that of the organic soil was peat collected from the aforementioned S. patens marsh. Nutrient treatments were based on a range of Mississippi River diversion discharge rates of nitrate, phosphate, sulfate, potassium, and iron as well as a control with no nutrient addition. After one summer, we found that total porewater conductivity increased with nutrient loading under both soil types. Under higher nutrient treatments the concentrations of porewater sulfide were elevated to phytotoxic levels, but this effect was only observed in the organic soil treatment. Nitrate and ammonium porewater concentrations were affected by both nutrient loading and soil type; however, nitrate was higher in the mineral soil while ammonium was higher in the organic soil. Porewater phosphorous and potassium concentrations were elevated in organic soil conditions and higher nutrient loading, while porewater iron was higher under mineral soil and lower nutrient loading. Aboveground standing crop, belowground biomass accumulation (i.e., ingrowth), and soil shear strength were also sampled at the end of the growing season with the goal of examining their relationships with nutrient and sediment enrichment and porewater chemistry.