PROBLEM TO BE SOLVED: To provide a method for cultivating plants reduced in nitric acid through utilizing bittern, by which plants having low nitrate-ion content are cultivated using a foliar spray agent or a soil watering agent easily available and readily regulating dilution thereof via a single material, and reducing nitrate-ion content in the plants, particularly in vegetables, so as to be utilized for health promotion/maintenance. SOLUTION: The method for cultivating plants reduced in nitric acid through utilizing bittern comprises possibly using bittern obtained from at least one kind selected from seawater, salt lake water and rock salt singly or in a blend of at least two kinds of salts. The bittern is diluted 500-10,000 times, preferably 1,000-5,000 times with well water or tap water when sprayed or watered as the foliar spray agent or the soil watering agent. The bittern to be applied is 5-10L or preferably 7L for 10 are (100m×10m). The agent may be sprayed or watered to the plants such as spinach once in 4th-10th day or preferably in 5th-7th day after germination, and further once after about one week, so as to obtain the plants greened-up and having the smaller content of the nitrate-ion at outer-leaf parts and inner-leaf parts. COPYRIGHT: (C)2006,JPO&NCIPI
