GREEN HOUSE AND ITS TYPES

 

GREEN HOUSE:

Approximately 92 percent of man-made plants are now cultivated in the open field. Farmers have had to deal with the growing conditions provided by Mother Nature since the dawn of agriculture. In temperate regions where climatic conditions are extreme and no crops can be grown, man has developed technological methods of growing high-value crops by providing protection from extreme cold and heat. Greenhouse Technology is the term for this. “The science of supplying plants with a favourable climate is known as greenhouse technology.” It also protects the plants from harsh climatic conditions including wind, cold, precipitation, and overwatering Excessive radiation, high temperatures, insects, and diseases are all factors to consider. Around the plants, an ideal microclimate can be formed. Greenhouses are framed or inflated structures covered in transparent or translucent material that are wide enough to grow crops under partial or full environmental control for optimal growth and productivity.

HISTORY:

Before 20th century- Agriculture development within protected structures began in the 19th century in France and the Netherlands. This method was used to create clear, low glass structures that provided climate protection and were primarily used to grow ornamental plants.

Modern Times - By the turn of the twentieth century, mainly after the end of World War II, greenhouse construction technology had advanced significantly, especially in colder parts of Western Europe, with the Netherlands leading the way. The structures were progressively upgraded with agro-technical systems, aeration solutions, and other accessories.

New Materials - By the end of the twentieth century, greenhouse technology had spread across northern and central Europe, spreading its reach and benefits to Israel, where a wave of experiments and research had begun in the region. In the 1960s, a new type of sheet-covering structure emerged. The lightweight, low-cost polyethylene sheets were the catalyst for a paradigm shift in greenhouse design.

New Technologies - The modular structure method (similar to Lego) leads to the development of growth technologies suitable for most types of crops, resulting in customised structure projects that are customer-tailored to specific needs. This new trend shattered the conventional, conservative Dutch hegemony that had previously ruled the greenhouse industry. Light-weighted structures with flexible polyethylene or stiff-flexible polycarbonate coverings are more popular and widespread nowadays than the mythical rigid glass greenhouses.

TYPES OF GREEN HOUSES

BASED ON SHAPE

BASED ON UTILITY

BASED ON CONSTRUCTION

BASED ON COVERING MATERIAL

BASED ON COST OF CONSTRUCTION

BASED ON SHAPE

types of greenhouses based on shape are:

1.     Lean to type greenhouse.

2.     Even span type greenhouse.

3.     Uneven span type greenhouse.

4.     Ridge and furrow type.

5.     Saw tooth type.

6.     Quonset greenhouse.

7.     Interlocking ridges and furrow type Quonset greenhouse.

8.     Ground to ground greenhouse.

LEAN TO TYPE GREEN HOUSE

When a greenhouse is built against the side of an existing structure, it is called a lean-to. It is constructed against a building, with one or more of its sides utilising the existing structure. It is usually attached to a house, but it can also be attached to other structures. The building's roof has been extended with appropriate greenhouse covering material, and the area has been properly enclosed. It is usually on the south side. The single or double-row plant benches with a total width of 7 to 12 feet are the only options for the lean-to greenhouse. It can be as long as the building to which it is attached. It should be oriented so that it receives the most sunlight.

ADVANTAGES:

It is probably limited to electricity, running water, and heat.

It is the most affordable structure.

This design maximises the use of sunlight while minimising the need for roof supports.

DISADVANTAGES:

There is a lack of space, light, ventilation, and temperature control.

The design's potential size is limited by the height of the supporting wall.

Temperature control is more challenging because the wall on which the greenhouse is built may collect heat from the sun while the translucent coat of the greenhouse may rapidly lose heat.

Greenhouse with an even span

The even-span structure is the most common and full-size structure, with two roof slopes of equal pitch and width. This design is used for a small greenhouse that is built on level ground. It is connected to a house at one of its gable ends. It can hold two or three rows of plant benches. The cost of the even greenhouse is higher than the cost of a lean-to type, but it has more design flexibility and can accommodate more plants. The even-span will cost more to heat due to its larger size and greater amount of exposed glass area. The shape of the design is better than a lean-to type for air circulation and temperature uniformity. during the heating season in the winter Unless the structure is very close to a heated building, a separate heating system is required. It will have two side benches, two walkways, and a large centre bench. In various parts of India, single and multiple span types are available for use. In general, the span of a single span type ranges from 5 to 9 m, while the length is around 24 m. The height ranges between 2.5 and 4.3 metres.

 

UNEVEN SPAN TYPE GREEN HOUSE

An uneven-span greenhouse is one that has one roof slope that is longer than the other. When located on a hilly terrain or to take advantage of solar angles, this is typically an adaptation of a regular greenhouse.

The roof in uneven-span greenhouses is not equal in width or pitch, hence the name, and the steeper angle faces south. The side that faces south is transparent, while the side that faces north is opaque to conserve energy.

 

ADVANTAGE

One roof wider than the others

Different pitch angles

It is used in hillsides and also wider roof faces.

RIDGE AND FURROW TYPE

The ridge and furrow greenhouse is made up of a series of even span greenhouses that are connected along the length of the greenhouse. All shared walls have been removed, allowing for more growing space. These greenhouses are sometimes referred to as gutter-connected greenhouses. Most commercial greenhouses used for floriculture and vegetable production use the ridge and furrow configuration.

ADVANTAGE

The lack of an inside wall beneath the gutter allows for greater efficiency.

DISADVANTAGE

Because the entire production area is a single space, the ability to maintain various environmental conditions (as would exist with multiple individual structures) is lost.

SAW TOOTH TYPE

Sawtooth Greenhouse Structures combine excellent ventilation with exceptional strength to withstand a variety of loads. In addition to the side ventilation, the roof ventilation alone provides 25% of the total ventilation of the covered area. The arches' shape allows for excellent light transmission. The use of various standard widths and wall heights emphasises flexibility and the practical use of growing space and conditions.

ADVANTAGE

The Sawtooth design has two major advantages: it is simple to instal exhaust fans mid-house in the vertical wall above the gutter, and it is built with columns that can extend through the roof to attach an energy truss outfitted with an exterior curtain.

QUONSET GREENHOUSE

A quonset greenhouse is a domeshaped structure that allows for maximum sun exposure. Quonset greenhouses have ventilation, heating, circulation fans, and improved environmental control. The quonset greenhouse has the advantage of working well on hillsides and maximising solar heating. The quonset greenhouse has the disadvantage of being more expensive and requiring more support due to its uneven structure.

Ground to Ground greenhouse

Short sidewalls are common in ground-to-ground greenhouses. It is a free-standing greenhouse structure used in reforestation for overwintering; ground to ground greenhouses can also be designed with environmental controls and purchased with a variety of different coverings.

Base on Utility

Greenhouses can be classified based on their functions or utilities. Among the various utilities, artificial cooling and heating of the greenhouse are the most expensive and inefficient.

elaboration Greenhouses are thus classified as green based on the use of artificial cooling and heating. Houses with active heating and cooling systems.

The utility of a greenhouse determines its type.

Ø  Greenhouses for active heating

Ø  Greenhouse for active cooling

Base on Construction

The structural material has the most influence on the type of construction, but the covering material also has an impact. The span of the house dictates the selection and construction of structural members. The greater the span, the stronger the material should be, and more structural members are used to create sturdy truss type frames. Simpler designs, such as hoops, can be used for shorter spans.

Greenhouses can thus be broadly classified based on construction as follows.

Ø  Wooden framed structures

Ø  Pipe framed structures

Ø  Truss framed structures

Base on covering material

The primary and most important component of the greenhouse structure is the covering materials.Covering materials have a direct impact on the greenhouse effect inside the structure, as well as the air temperature inside. The types of frames and methods of attachment vary according to the covering material. Glass, plastic film, and rigid panel greenhouses are the three types of greenhouses based on their covering materials.