Rice plants were grown in nutrient solution containing Si/FeEDTA and LED light. Plants grown distant from the light source could get effect carried by the circulation of nutrient solution. The solution containing Fe (100 mg∙L^-1, FeEDTA) and Si (100 mg∙L^-1, K₂SiO₃) was illuminated separately by sunlight and LED-purple in the solution. The OD₄₀₀ of the solution increased with each illuminating day. The chemical change induced by illumination occurred between FeEDTA and K₂SiO₃. This chemical change was not related to solution temperature (°C) but was related to illumination only, so this was a photochemical reaction. The illuminated solution resulted in light absorbance from OD₃₆₀ to OD₅₆₀. An FeEDTA-SiO₃ complex was isolated from the solution illuminated by LED blue or sunlight. This complex was again absorbed by a lining membrane to form a three-component complex. There was a large amount of complex (e.g., microcrystals) accumulated on the lining membrane. LED-purple, LED-red and LED-infrared could be induced to result in the FeEDTA-SiO₃ complex. Chlorella beijerinch in the nutrient solution containing the FeEDTA-SiO₃ complex grew well; dead algae broke down and left a brown-coloured fluffy ball of Fe-Si complex. The rice plants fed the FeEDTA- SiO₃ complex showed high dry weight per plant.