Abstract: A soil or soil improver for plants which is characterized by combining a charcoal or activated carbon on which oxygen is adsorbed with a soil or soil improver comprising an inorganic or organic ion exchanger and a porous mineral, and a soil or soil improver which further comprises polyacrylamide. By using the soil or soil improver of the invention, plants can continue to grow for four months to one year without supplying water and fertilizer, and various decoration patterns of plants are possible, such as horizontal decoration, reverse decoration and space decoration.