For many gardeners, the onset of fall brings with it an unwelcome pause in a favorite activity--growing beautiful plants. As winter approaches, more and more gardeners' thoughts turn to owning a greenhouse to fill the void. But gardeners should consider carefully before making the commitment to what could be a costly and permanent structure.
Function of Greenhouses
Not all greenhouses are the same, the primary difference being whether they're three-season or four-season greenhouses. A three-season greenhouse provides gardeners with an extension of the growing season. Gardeners can start seeds well before the frost date in the spring and can keeping growing plants even after a hard frost hits in the fall. Usually, however, a three-season greenhouse won't protect plants through the below-freezing weather of deep winter. For that, gardeners turn to a four-season greenhouse.
A four-season greenhouse is usually made of thicker glass or plastic, is better insulated and has a heating system, either gas or electric. With a four-season greenhouse, gardeners even in the upper Midwest and northern states can grow plants all year long. But with thicker walls and heat comes a higher price tag too. Usually only serious gardeners will commit to a four-season greenhouse, given the high cost of owning, heating and maintaining such a structure.
Types of Greenhouses
Greenhouses come in all shapes and sizes and can be freestanding or attached to an existing building. Some homes are built with a "greenhouse room" that can be used either part-time or year-round. Lean-to greenhouses that are added to the side of an existing building are a popular option. Freestanding greenhouses can be beautiful permanent structures made of glass, wood and metal, complete with gingerbread trim, watering systems and indoor lighting or they can be temporary structures made from plastic sheeting, straw bales and livestock fencing panels.
Greenhouses--whether three-season or four-season--usually include many of the same components. These include transparent walls made of either glass or plastic which allow the sun's rays to enter but not escape entirely, thus heating the interior. Automatic ceiling vents help to alleviate excessive heating in the summer but can be closed during cooler weather to trap heat. Sun shades can be used on the roof during hot summer months to cool the interior. Shelves and potting benches provide surface area for harboring plants. Bars suspended from the ceiling provide options for hanging pots. Floors can be made of a variety of materials, including brick, tile or paving stones or less expensive options such as pea gravel or mulch.
Building a Greenhouse
Building a greenhouse can be as simple as looking up instructions for an inexpensive temporary structure online and making a quick trip to the local hardware store, or as complicated as hiring a professional contractor and committing to a months-long building project. Many do-it-yourself greenhouse kits are also available for gardeners who are also handy with tools.