A plant growing device (2, 3) includes an envelope (21,31) and a plant growing medium (22). The envelope (21,31) is made of a sheet material and has substantially planar first and second walls (211,311,231,331), a surrounding wall (210,310) connected between the first and second walls (211,311,231,331), and a plurality of openings (232,332) formed in the second wall (231,331) and adapted to permit extension of plants (9). The plant growing medium (22) is enclosed by the envelope (21,31), and includes a water-absorptive material selected from a polymeric foam, saw dust, charcoal, soil, sand, wood pulp, polymeric fibrous substances, and natural fiber materials.一種栽種介質，用以供栽種植物並包含一底層單元、一介質單元及一頂層單元，底層單元包括一呈薄層狀的第一本體及複數貫穿第一本體之第一開孔，介質單元設置於底層單元上，介質單元的材質是選自由高吸收性樹脂、木漿、木屑、炭及棉質所構成的群組，而頂層單元遮蓋於介質單元上，頂層單元包括一呈薄層狀的第二本體及複數貫穿第二本體的第二開孔。
