How Greenhouses Work

Greenhouse Features

A greenhouse in Queen Elizabeth Park, Vancouver
Darlyne A. Murawski/National Geographic/Getty Images

Although greenhouses look like simple structures, there's more to them than meets the eye. A reliable frame, covering, flooring and ventilation are all necessary for basic operation. To sustain the environment, a heating system and some automated processes, like irrigation via a dedicated water supply, may also be necessary.

The Frame: A sturdy frame is necessary to maintain the plastic or glass panels that let in precious light and capture heat in the greenhouse. Larger greenhouses also need a foundation. The frame can be made of any number of materials, the most common of which are aluminum, wood, rigid PVC and galvanized steel. Aluminum lets in more light and can also support clip-on panels, making it the most common choice.


The Coverings: Often referred to as glazing, the panels that cover greenhouses are specially designed to let in as much of the sun's radiation as possible. Ideally, they also provide insulation, are impervious to deterioration from ultraviolet radiation and are shatterproof. The panels can be made of heavy glass or any of a number of synthetic materials designed to maximize light exposure and help reduce heat loss. Glass lets in about 90 percent of the sun's radiation, helping to retain heat and hold up to ultraviolet light [source: Hessayon]. Synthetics, while cheaper and sometimes stronger than glass, let in less of the sun's rays.

The Flooring: Greenhouses can have very simple flooring made of wooden slats, or even a pressed dirt floor. Where conservatories usually have finished floors, work-a-day greenhouses will often have dirt around the perimeter and pea shingle, wood, concrete or stone walkways.

Exploring plants as a hobby has never been easier. Greenhouses are now less expensive to buy or build than ever before. From prefabricated kits that can be purchased on the Internet to lighter and sturdier materials for building your own, owning a greenhouse is no longer a distant dream for the average gardener. Keeping and cultivating plants is a popular pastime worldwide, and greenhouses can extend the seasonal growing time for amateurs and professionals. So what's involved in building a green house of your own? Read on to find out.