Why do greenhouses have different types?
There are various types of greenhouses based on the utility and functions. Out of the different utilities artificial heating and cooling systems are much more expensive and complicated. They require the help of a professional to install. The type of greenhouses is largely dependent on factors such as plants to be grown in the greenhouse, area size of the land on which the greenhouse is to be installed, cost and budgeting of the owner and other related factors.
Greenhouse types based on utility:
- Greenhouse for active cooling: This refers to a greenhouse where the temperatures inside the greenhouse must be reduced to attain the desirable climate for the plants to grow in. This can generally be seen in summer where the external environment is too hot to promote plant growth.
- Greenhouse for active heating: This refers to a type of greenhouse where the air temperature decreases at night or in winters. To avoid damage to the plants artificial heat should be generated based on the rate of heat energy that is lost. There are many methods that can be employed to prevent extensive heat loss such as using a double layer polyethene film or thermos pane glass panels.
Greenhouse types based on Covering Material:
- Glass greenhouse: This refers to a greenhouse where glass is used as the primary material to build the walls and roof of the greenhouse. Using glass enables higher penetration of natural sunlight and higher air infiltration rates. This ensures lower humidity inside the greenhouse and helps in preventing plant disease.
- Rigid panel greenhouse: This refers to a greenhouse that is constructed with Polyvinyl Chloride rigid panels, acrylic and polycarbonate rigid panels or fiber glass reinforced rigid panels. These panels provide a ridge and furrow type of framework to the greenhouse and the material is much more resistant to breakage as compared to glass panels. Their life is up to 20 years and they require minimum maintenance.
- Plastic film greenhouses: This refers to a greenhouse that is constructed with plastic films that include polyethene and polyester. These materials are becoming extremely common as they are cheap and the cost of heating is relatively cheaper as compared to a glass greenhouse. However, they do not have a long life and need to be replaced every 3 to 4 years.
Greenhouse types based on construction:
- Wooden frame structure: This refers to a greenhouse with a span less that 6 meters where wooden framed structures are used to construct the side posts and columns inside the greenhouse. Pine wood and timber wood with good strength, durability and machinability can be used for constructing these greenhouses.
- Pipe framed structure: This refers to a greenhouse where the side posts, columns, purlins and cross ties are constructed using pipes. The area inside the greenhouse is generally around 12 meters.
- Truss framed structure: This refers to a greenhouse where the area is generally above 15 meters and truss frames are used for the construction. A truss is made by welding together flat steel and tubular steel and encompasses chords and struts. These support support members under tension and compression respectively. Most of the glass greenhouses are of this structure.
The type of greenhouse that is suitable should be analyzed thoroughly and it is advised to seek professional help before investing in the actual structure of the greenhouse. All the different types of greenhouses have their own pros and cons which when understood thoroughly can help lead to better decision making and avoid any shortcomings in the future and ensure optimum plant growth.