Pot experiments were performed in the North Carolina State University greenhouse using Phosphogypsum/clay tailing from the Potash Corporation of Saskatchewan (PCS) phosphate mine site which contained about 2:1 Zn:Cd ratio. In the first season, lettuce plants (Lactuca sativa var. Parris Island) were grown on the PCS soil with increased Zn content (2:1, 5:1, 25:1, 50:1, 75:1, 100:1, 125:1, 150:1 and 200:1 Zn:Cd ratio) and with four levels of rock phosphate (0.5%, 1%, 2.5% and 5%). The residual effect of these treatments were determined by growing swiss chard plants (Beta vulgaris var. Lucullus) on the same treated soils. Five Zn:Cd ratios (2:1, 25:1, 100:1, 150:1 and 200:1) were used with the application of 1or 3% of composted leaves to determine the effect of organic material along with Zn applications on swiss chard uptake of Cd. The obtained results indicated that Cd concentration in lettuce plants was significantly and gradually decreased from 69.95 ppm to 29.64 ppm in the plants grown on the original PCS soil and the soil treated with 50:1 Zn:Cd ratios, respectively. Whereas the decrease of Cd concentrations in swiss chard plants was from 40.41 ppm to 32.11 ppm in plants grown on the original PCS soil and the soil with 25:1 Zn:Cd ratio, respectively. Compared with the original PCS soil, the application of 5% rock phosphate significantly decreased Cd uptake from 19.00 ppm to 12.59 ppm and from 35.17 ppm to 28.19 ppm in Lettuce and Swiss Chard plants, respectively. The application of 3% composted leaves generally decreased the amounts of Cd uptake by swiss chard plants. The goal of this study was to decrease the plant uptake of Cd by increasing Zn content with and without the application of organic material and also by rock phosphate application.