Provided are a method for cultivating a plant in a transparent sealed container and a medium therefor. A transparent nutrient solution and a gellan gum are mixed, and then the mixture gels to form the medium. An amount of the gellan gum added to the nutrient solution is 2-10g/L. The medium has a pH value of 3.5-10.0. The gellan gum serves as a sole transparent gelling agent, thereby ensuring uniformness and transparency of the transparent medium. Moreover, the gellan gum possesses good adherence, such that the medium can be securely adhered to a transparent sealed container. An experiment proved that when the transparent sealed
