14"" deep The Riga IV Greenhouse has a unique optional two layer shelving system with removable shelf inserts to allow taller plants to grow unobstructed, The shelving is suspended from the ceiling without braces underneath allowing for more storage space for gardening tools like a wheelbarrow or long tools inside the greenhouse, The top shelf hangs forward for easier reaching accessibility without blocking outside light from reaching the bottom shelf, The shelves are made from a twin wall polycarbonate material, allowing for much better and more even light distribution through the greenhouse to help with plant growth, One top shelf -Strong enough to hold several flats of plants, Shelves are hanging from chains and are stronger then traditional braces, Overall dimensions: 168"" W x 14"" D, Two top shelves can fit in each greenhouse, For use with Riga IV Greenhouse and Riga IVs Greenhouse, SKU: EXTR099