The invention includes a box, vertical and horizontal dividers, a plant-growth mat, and a mounting bar. The dividers are permanently linked to form an insert, which slides into insert grooves inside the box. Insert grooves have upper and lower rails. At the insert groove openings rail ends feature upward bends. The plant-growth mat is secured against the box inner-back by the insert which is prevented from sliding out by the upward bends of the lower rails. A support mount and a fastener on the back of the box and compatible groove surfaces on the mounting bar prevent box movement when mounted. The invention increases the rigidity of the dividers and reduces their deformability. It facilitates inserting the integrated dividers into the box with convenient insert grooves. The plant-growth mat can store water, prevent soil erosion, and provide aeration to plant roots. The mounting bar stabilizes the module for easy installation.
