Summer cover crops were grown and incorporated into the soil, and compost as organic mulch with different rates was applied to study their effects on soil fertility and tomato production. The cover crops were sunn hemp, velvetbean, cowpea and sorghum sudangrass vs. fallow as a control, the rates of compost were 25, 50, 75 Mg/ha for one year and 50 Mg/ha for two consecutive years compared to the control (without organic mulch). The result showed that leguminous cover crops, especially sunn hemp, improved soil fertility and tomato production significantly. Among different rates of organic mulch, 50 Mg/ha applied in two consecutive years increased soil fertility and produced the highest tomato marketable fruit yields. This result shows a high potential of using cover crops and organic mulch to improve sustainable agriculture and organic farming in subtropical regions.