The purpose of a greenhouse is to shelter tender plants from natural elements such as wind, rain, frost, and temperature extremes. Basic greenhouse construction begins with choosing a location in a sunny area that is shielded from the wind by trees or buildings. Next, decide on the size and design for the greenhouse construction. Then determine the type of construction materials needed and build the frame. Secure the wall covering material to the frame and install any heaters, fans, lighting, or irrigation systems that will be utilized.
Before beginning any type of greenhouse construction, carefully choose a location that is shielded from the wind. If trees or buildings are present, try to build the greenhouse in a sunny area on the south side of them. This location will help maximize the amount of heat retained inside the structure and reduce the need for additional heating resources. Another consideration is the availability of electrical power for fans, heaters, or lighting that may be needed. If a fixed water line will be used, the greenhouse should be placed as close as possible to the main water supply.
The next step in greenhouse construction is to determine the size of the structure. It is usually better to build a slightly larger greenhouse then necessary to allow for future expansion. The extra materials and labor required for a larger structure will usually be less expensive if installed during the original greenhouse construction. Then decide on the basic design for the greenhouse. Designs range from small structures attached to the window or wall of a house to larger freestanding greenhouses with their own heating, ventilation, cooling, lighting, and irrigation systems.
The process continues with the purchase the building materials needed to construct the foundation, and the framing of the greenhouse. Install a raised wooden floor or poured concrete slab before constructing the upper framework. If a square or rectangular design is chosen, it may be less costly and time consuming to buy a prefabricated outbuilding kit and use only the foundation and framing materials for the structure. Semi-circular, Quonset-type designs can be easily constructed with steel reinforcement bars and rigid PVC pipe for the frame. Smaller greenhouse frames can also be constructed with galvanized pipe and fittings.
Once the frame is completed, securely fasten the wall and roofing materials to it. In warmer climates, semi-transparent plastic sheeting may be utilized for the walls and roof. Colder climates will probably require thicker material such as corrugated fiberglass panels or transparent rigid plastic for better heat retention. Install any doors, windows, or irrigation piping needed. Then connect all lighting fixtures, ventilation equipment, fans, or heaters to complete the greenhouse construction.