This study aims to identify the effect of salted water on the growth of green mustard plants (Brassica juncea L) and determine the appropriate dosage of cow manure in increasing the growth and yield of green mustard plants. The study was conducted using a completely randomized design method (CRD) with 2 treatment factors, namely: Treatment of doses without cow manure, 10 tons per Ha cow manure, 20 tons per Ha cow manure, and 30 tons per Ha cow manure with no concentration NaCl solution, 5000 ppm concentration of NaCl solution, 7500 ppm concentration of NaCl solution. 10,000 ppm concentration of NaCl solution. The high concentration of NaCl (hypertonic) solution will reduce the potential of water in the cell membrane, so that the release of the plasma membrane from the plant cell wall repeatedly will cause plasmolysis. From this study it was found that the treatment of salt water stress on mustard greens gave a bad impact on production results.