The Lifetime 60065 Raised Garden Bed 4 ft x 4 ft gives you the perfect garden setup in less than one hour. It is constructed of UV-protected high-density polyethyene (HDPE) with a simulated wood design. It is low-maintenance, weather resistant, and will not rot, crack or peel. The walls are 9 inches high, and two beds can be stacked together to create 18 inch walls to accommodate deep rooted plants, or even a child's sandbox. With its easy do-it-yourself assembly and low-maintenance features, gardening has never been this easy.