The greenhouse is an inflated structure covered with transparent or translucent materials such as glass or plastic in which commercially valuable fruits, flowers and vegetables can be grown under controlled climatic conditions or a partially controlled environment. In a nutshell, a greenhouse provides the optimum climatic conditions for crops in such places, where traditional cultivation of those crops is not possible.
Advantages of Greenhouse Farming.
The advent of greenhouse farming accelerated very rapidly and is now a common phenomenon in the scenario of Indian agriculture. This happened due to its large number of advantages. Following are some of the very important benefits of greenhouse farming –
· Crop cultivation can be carried out under a controlled environment.
· Greenhouse provides an excellent opportunity for the cultivation of expensive foreign fruits and vegetables which grow only in the very warm and humid equatorial region and thus can fetch high value in the export markets.
· It provides the opportunity of cultivating crops all the year-round to meet the ever-increasing market demands.
· In view of the rapid urbanization, a greenhouse provides an opportunity to cultivate crops in limited land resources.
· The venture of greenhouse farming generates the scope of employment for the youths in the locality.
· Greenhouse is the best place for research and evolution of new improved hybrid varieties of plants and seeds.
Types of greenhouse.
Based on the type of covering material, a greenhouse can be divided into –
· Polyhouse – the type of greenhouse where the covering material is transparent or translucent polythene.
· Fiber-reinforced plastic house – the covering material is made up of transparent or translucent fiber and plastic.
· Glasshouse – the covering material is fully made of glass.
Based on the type of environmental control, the greenhouse can be divided into –
· Naturally ventilated greenhouse
· Evaporation cooled greenhouse
· Hi-tech greenhouse
Working Principle of Greenhouse.
Greenhouse operates on a physical principle termed as the “greenhouse effect”. The sunlight coming from the sun to our earth is short in wavelength. It passes easily through the transparent, translucent or semi-transparent material of the greenhouse and enters into the greenhouse. But, when the light of short wavelength hits an opaque surface like plant leaves or greenhouse floor, some of the light energy changes into heat energy and thus the reflected light becomes longer in wavelength. The greenhouse panels can only transmit light of shorter wavelength and neither light of longer wavelength nor heat. So, the reflected ray again reflects back into the surface and the temperature of the greenhouse increases and remains controlled.
This property becomes hugely beneficial for temperate and cold countries where barely any crops can grow naturally under traditional agriculture.
Site selection for greenhouse.
Selecting a perfect site for the greenhouse is the most important part of greenhouse farming.
· Connectivity of the greenhouse to local roads and market should be excellent.
· Windy and waterlogged areas should be avoided.
· Industrial areas should be avoided for potential pollution threats.
· Well drainage and sufficient area for future expansion are needed.
The environment of the greenhouse.
· Periodic sprinkling of water on the cover for maintaining temperature.
· Ridge openings and nets should be a part of the house for natural ventilation.
· Over ganging misting or fogging systems should be used for ideal control.
· Mechanical ventilation should be provided by means of exhaust fans.
Maintenance of the greenhouse.
Maintaining the greenhouse is as important as doing farm activities inside it. The various types of maintenance procedures include –
· Clearance of dust by washing the covers periodically.
· Changing the polythene covers every five years due to the loss of their transparency and transmissivity power.
· UltraViolet insect killers should be installed for controlling pests and diseases.
· Periodic cleaning of irrigation and fertigation pipes and ventilation nets.