Greenhouses are available in all sizes, shapes and degrees of strength. They can be bought in unassembled packages, assembled on site and ready to set on foundations, or custom designed for a specific need. Most greenhouse structures fall into three types. The attached lean-to greenhouse has one sidewall as a part of a house, garage or other building. The lean-to is less expensive to operate and construct, but there may be some drawbacks in cooling or ventilating this type of greenhouse.
The window design greenhouse is attached outside a conveniently located window and may be an economical solution for some homeowners. It’s very challenging, however, to maintain a uniform temperature in this type of greenhouse because heat is dependent on the interior home heating.
The free-standing greenhouse is the most versatile, when maintaining a good greenhouse environment. This type of greenhouse is easy to ventilate all year long, and can be easily expanded if necessary.
When considering where to place the greenhouse, consider the exposure the greenhouse would receive from a certain location. An eastern or southern exposure is the best for the lean-to greenhouse. Locate the greenhouse out of shade, especially in the winter months.
Materials for the framing of the greenhouse may be composed of untreated wood, aluminum alloy, steel stone or brick. The material you may decide upon will depend on the budget, durability, types of plants to be grown and aesthetics of the structure. If a wood framework is chosen, use a type without wood preservatives, such as Penta or creosote. The most popular woods, western red cedar or Douglas fir, resist rotting and are a good choice for greenhouses. Aluminum and steel are generally colder than wood but in small greenhouses the amount of heat loss due to this factor is limited. Aluminum generally requires less maintenance than a wood structure.