This Harbour Housewares 3-Tier Walk-in Polyethylene Greenhouse offers a great, practical shelter in which to cultivate and grow a wide variety of seedlings, fruits, vegetables and flowers.When choosing your greenhouse, there are two key components to consider: the framework that makes up the structure itself, and the material that covers it. Our Harbour Housewares Greenhouses are constructed from a galvanised steel framework. The inherent strength of steel allows for a far slighter, more open framework than alternatives such as wood and plastic, which means a greater number of larger gaps for sunlight to pass through.That steel frame is then covered by a reinforced polyethylene cover. More flexible and affordable than glass or solid plastic, polyethylene greenhouses typically retain up to 40% more heat than glass, making them an ideal environment for plants that require a warmer temperature. The opaque finish also diffuses the sunlight as it passes through, spreading it across a wider